Encore -- d:(Boundary layer transition)

Experimental study of the effects of isolated roughness elements on the stability and transition of a hypersonic boundary layer on a flat plate.

Liu, Shicheng;Dong, Hao;Jiang, Yinglei

Academic Journal | Physics of Fluids. Feb2024, Vol. 36 Issue 2, p1-13. 13p. Please log in to see more details

Surface roughness elements on hypersonic vehicles can cause early boundary layer trans... more

Experimental study of the effects of isolated roughness elements on the stability and transition of a hypersonic boundary layer on a flat plate.

Physics of Fluids. Feb2024, Vol. 36 Issue 2, p1-13. 13p.

Surface roughness elements on hypersonic vehicles can cause early boundary layer transition, increasing wall skin friction and heat flux and affecting aircraft range and thermal protection systems. Accurate prediction of the transition caused by these roughness elements is crucial for the design of hypersonic vehicles. In this work, wind tunnel experiments on isolated roughness-induced boundary layer transition at Ma = 6 are conducted. Infrared thermography and high-frequency pressure sensors are utilized to investigate the effects of different roughness element configurations (cylindrical, diamond, ramp) on the hypersonic boundary layer instability and transition. The experimental results show that all three roughness elements can effectively enhance the generation of second mode waves and promote boundary layer transition. Compared to smooth surfaces, they exhibit similar frequency band range, faster growth, and earlier saturation. Among them, the ramp roughness element most effectively triggers the boundary layer transition, with a relatively small heat flux increase. Furthermore, bispectral analysis illustrates that all three roughness elements undergo self-interactions that lead to spectral broadening, ultimately resulting in boundary layer transitions. [ABSTRACT FROM AUTHOR]

Subject terms:

BOUNDARY layer (Aerodynamics) - TRANSITION metals - WIND tunnels - PRESSURE sensors - HEAT flux

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RT Journal Article A1 Liu, Shicheng A1 Dong, Hao A1 Jiang, Yinglei T1 Experimental study of the effects of isolated roughness elements on the stability and <highlight>transition</highlight> of a hypersonic <highlight>boundary</highlight> <highlight>layer</highlight> on a flat plate. FD Physics of Fluids. Feb2024, Vol. 36 Issue 2, p1-13. 13p. YR 2024 OP 13 VO 36 IS 2 DO 10.1063/5.0187029 SP 1 JF Physics of Fluids SN 10706631

Overview of Research Progress on Numerical Simulation Methods for Turbulent Flows Around Underwater Vehicles

He, Kangjian;Pan, Zhi;Zhao, Weiwen;Wang, Jianhua;Wan, Decheng

Academic Journal | Journal of Marine Science and Application. 23(1):1-22 Please log in to see more details

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RT Journal Article A1 He, Kangjian A1 Pan, Zhi A1 Zhao, Weiwen A1 Wang, Jianhua A1 Wan, Decheng T1 Overview of Research Progress on Numerical Simulation Methods for Turbulent Flows Around Underwater Vehicles FD Journal of Marine Science and Application. 23(1):1-22 YR 2024 OP 22 VO 23 IS 1 DO 10.1007/s11804-024-00403-8 SP 1 JF Journal of Marine Science and Application SN 16719433

Effect of wall blowing/suction on roughness-induced transition in high-speed boundary layers.

Zhao, Xiaohui;Zhang, Qinghu;Wan, Bingbing;Chen, Cheng

Academic Journal | Acta Mechanica. Jul2022, Vol. 233 Issue 7, p2737-2745. 9p. Please log in to see more details

A Mach 5 boundary layer transition flow induced by distributed roughness elements of r... more

Effect of wall blowing/suction on roughness-induced transition in high-speed boundary layers.

Acta Mechanica. Jul2022, Vol. 233 Issue 7, p2737-2745. 9p.

A Mach 5 boundary layer transition flow induced by distributed roughness elements of ramp shape is studied using implicit large eddy simulation. Wall blowing/suction is introduced into the boundary layer with different values of frequency and amplitude for the investigation of its effect mechanism on the transition process dominated by the influences of distributed roughness elements. The wall blowing/suction disturbances with frequencies close to the fundamental mode, derived by linear stability theory (LST) analysis of local profiles, are shown to lead to an upstream shift of the transition location, which is strongly relevant to the disturbance growth in the sharp shear layer induced by the roughness elements, with a greater amplitude causes a more notable acceleration of the transition. As for those with frequencies further away from the fundamental mode, the control efficiencies are inapparent. [ABSTRACT FROM AUTHOR]

Subject terms:

BOUNDARY layer (Aerodynamics) - TRANSITION flow - STABILITY theory - ACCELERATION (Mechanics)

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RT Journal Article A1 Zhao, Xiaohui A1 Zhang, Qinghu A1 Wan, Bingbing A1 Chen, Cheng T1 Effect of wall blowing/suction on roughness-induced <highlight>transition</highlight> in high-speed <highlight>boundary</highlight> <highlight>layers</highlight>. FD Acta Mechanica. Jul2022, Vol. 233 Issue 7, p2737-2745. 9p. YR 2022 OP 2745 VO 233 IS 7 DO 10.1007/s00707-022-03244-0 SP 2737 JF Acta Mechanica SN 00015970

An adjoint-based methodology for calculating manufacturing tolerances for natural laminar flow airfoils susceptible to smooth surface waviness

Moniripiri, Mohammad;Brito, Pedro P. C.;Cavalieri, André V. G.;Sêcco, Ney R...

Academic Journal | Theoretical and Computational Fluid Dynamics. 38(1):15-37 Please log in to see more details

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RT Journal Article A1 Moniripiri, Mohammad A1 Brito, Pedro P. C. A1 Cavalieri, André V. G. A1 Sêcco, Ney R. A1 Hanifi, Ardeshir T1 An adjoint-based methodology for calculating manufacturing tolerances for natural laminar flow airfoils susceptible to smooth surface waviness FD Theoretical and Computational Fluid Dynamics. 38(1):15-37 YR 2024 OP 37 VO 38 IS 1 DO 10.1007/s00162-023-00681-y SP 15 JF Theoretical and Computational Fluid Dynamics SN 09354964

Visualization study on boundary layer transition using surface arc plasma actuators

Gan, Tian

Academic Journal | Journal of Visualization. 27(1):43-57 Please log in to see more details

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RT Journal Article A1 Gan, Tian T1 Visualization study on <highlight>boundary</highlight> <highlight>layer</highlight> <highlight>transition</highlight> using surface arc plasma actuators FD Journal of Visualization. 27(1):43-57 YR 2024 OP 57 VO 27 IS 1 DO 10.1007/s12650-023-00951-1 SP 43 JF Journal of Visualization SN 13438875

Turbulent-turbulent transient concept in pulsating flows.

Taylor, P. S.;Seddighi, M.

Academic Journal | Journal of Fluid Mechanics; 3/10/2024, Vol. 982, p1-43, 43p Please log in to see more details

The turbulence behaviour of current-dominated pulsating flows has been investigated. D... more

Turbulent-turbulent transient concept in pulsating flows.

Journal of Fluid Mechanics; 3/10/2024, Vol. 982, p1-43, 43p

The turbulence behaviour of current-dominated pulsating flows has been investigated. Direct numerical simulations have been carried out for Stokes lengths over a range of l+ s = 5-26, and amplitudes spanning 90% of the current-dominated regime, about a mean flow of Re = 6275. The results show that the turbulence response in intermediate and low-frequency pulsations is governed by a multistage turbulent-turbulent transition process, which bears a strong similarity to the multistage response of non-periodic acceleration. During the early acceleration period, the flow enters a pretransition stage, in which a new laminar perturbation boundary layer forms at the wall, and the streamwise velocity streaks are stretched. If the low-speed streaks destabilise prior to the deceleration period, then the flow enters a transition stage in which the perturbation boundary layer undergoes a bypass-like transition process. A unique feature of pulsating flows is the ongoing mechanism of turbulence decay, which initiates during the deceleration period and constitutes the main transient turbulence mechanism for much of the cycle. For high-frequency pulsations, the perturbation boundary layer fails to reach the pretransition stage prior to the deceleration period. Instead, the flow alternates between two inertial stages which are characterised by two layers of amplified viscous force; one growing at the wall, and one detached and moving towards the core. [ABSTRACT FROM AUTHOR]

Subject terms:

LAMINAR boundary layer - BOUNDARY layer (Aerodynamics) - STREAMFLOW velocity - VISCOSITY - TRANSITION flow - TURBULENT boundary layer

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RT Journal Article A1 Taylor, P. S. A1 Seddighi, M. T1 Turbulent-turbulent transient concept in pulsating flows. FD Journal of Fluid Mechanics; 3/10/2024, Vol. 982, p1-43, 43p YR 2024 OP 43 VO 982 DO 10.1017/jfm.2023.1025 SP 1 JF Journal of Fluid Mechanics SN 00221120

Exploring the boundary layer transition of hypersonic flow over a compound delta wing.

Ullah, Habib;Qiu, Hongtian;Yu, Ganglong;Ijaz Khan, M.;Lee, Cunbiao

Academic Journal | Physics of Fluids. Mar2024, Vol. 36 Issue 3, p1-12. 12p. Please log in to see more details

The boundary layer transition on a compound delta wing for Mach 6 has been studied exp... more

Exploring the boundary layer transition of hypersonic flow over a compound delta wing.

Physics of Fluids. Mar2024, Vol. 36 Issue 3, p1-12. 12p.

The boundary layer transition on a compound delta wing for Mach 6 has been studied experimentally and numerically. The experiment was performed at Peking University quiet wind tunnel using the Rayleigh scattering flow visualization and infrared thermography. Direct numerical simulations, under the same flow conditions, are applied to analyze the transition mechanism. The results show that the traveling cross flow vortices first appear near the leading edge of compound delta wing. These vortices modulate the mean profile of the flow due to which a rope-like structure appear in the streamwise direction, which is typical of Mack's second-mode. As Mack's second-mode grows to a sufficiently large amplitude, it triggers secondary instability, which behaves as secondary finger like structures. At the end of the transition process, low-frequency waves are excited by Mack's second-mode through an interaction mechanism with their phase speed approaching each other. It is also found that increasing the unit Reynolds number greatly promotes the aerodynamic heating as well as local hot streaks appear on both sides of the compound delta wing in the streamwise direction. The appearance of hot streaks on the compound delta wing is strongly correlated with Mack's second-mode. [ABSTRACT FROM AUTHOR]

Subject terms:

PEKING University (Beijing, China) - BOUNDARY layer (Aerodynamics) - TRANSITION flow - HYPERSONIC flow - RAYLEIGH flow - AERODYNAMIC heating

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RT Journal Article A1 Ullah, Habib A1 Qiu, Hongtian A1 Yu, Ganglong A1 Ijaz Khan, M. A1 Lee, Cunbiao T1 Exploring the <highlight>boundary</highlight> <highlight>layer</highlight> <highlight>transition</highlight> of hypersonic flow over a compound delta wing. FD Physics of Fluids. Mar2024, Vol. 36 Issue 3, p1-12. 12p. YR 2024 OP 12 VO 36 IS 3 DO 10.1063/5.0202268 SP 1 JF Physics of Fluids SN 10706631

Chirality-induced Lineage Enforcement of Mechanosensitive Mesenchymal Stem Cells Across Germ Layer Boundaries.

Das, Ankita;Adhikary, Shreya;Chowdhury, Amit Roy;Barui, Ananya

Academic Journal | Stem Cell Reviews Apr2024, Vol. 20 Issue 3, p755-768, 14p Please log in to see more details

Mesenchymal to epithelial transition (MET) is instrumental in embryogenesis, tissue re... more

Chirality-induced Lineage Enforcement of Mechanosensitive Mesenchymal Stem Cells Across Germ Layer Boundaries.

Stem Cell Reviews Apr2024, Vol. 20 Issue 3, p755-768, 14p

Mesenchymal to epithelial transition (MET) is instrumental in embryogenesis, tissue repair, and wound healing while the epithelial to mesenchymal transition (EMT) plays role in carcinogenesis. Alteration in microenvironment can modulate cellular signaling and induce EMT and MET. However, modulation of microenvironment to induce MET has been relatively less explored. In this work, effect of matrix stiffness in mediating MET in umbilical cord-derived mesenchymal stem cells (UCMSC) is investigated. Differential segregation of cell fate determinant proteins is one of the key factors in mediating altered stem cell fates through MET even though the genesis of apicobasal polarity remains ambiguous. Herein, it is also attempted to decipher if microenvironment-induced asymmetric cell division has a role to play in driving the cells toward MET. UCMSC cultured on stiffer PDMS matrices resulted in significantly (p < 0.05) higher expression of mechanotransduction proteins. It was also observed that stiffer matrices mediated significant (p < 0.05) upregulation of the polarity proteins and cell fate determinant protein, and epithelial marker proteins over lesser stiff substrates. On the contrary, expression of inflammatory and mesenchymal markers was reduced significantly (p < 0.05) on the stiffer matrices. Cell cycle analysis showed a significant increase in the G1 phase among the cells seeded on stiffer matrices. Transcriptomic studies validated higher expression of epithelial markers genes and lower expression of EMT markers. The transition from mesenchymal to epithelial phenotype depending on the gradation in matrix stiffness is successfully demonstrated. A computational machine learning model was developed to validate stiffness-MET correlation with 94% accuracy. Summary: The cross-boundary trans-lineage differentiation capability of MSC on bioengineered substrates can be used as a potential tool in tissue regeneration, organogenesis, and wound healing applications. In our present study, we deciphered the correlation between YAP/TAZ mechanotransduction pathway, EMT signaling pathway, and asymmetric cell division in mediating MET in MSC in a substrate stiffness-dependent manner. It is inferred that the stiffer PDMS matrices facilitate the transition from mesenchymal to epithelial state of MSC. Further, our study also proposed a scoring system to sort MSC from an intermediate hybrid E/M population while undergoing graded MET on matrices of different stiffnesses using a machine learning technique. This proposed scoring system can provide information regarding the E/M state of MSC on different bioengineered constructs based on their biophysical properties which may help in the proper choice of biomaterials in complex tissue-engineering applications. [ABSTRACT FROM AUTHOR]

Subject terms:

MESENCHYMAL stem cells - EPIBLAST - GERM cells - EPITHELIAL-mesenchymal transition - BOUNDARY layer (Aerodynamics) - BIOMATERIALS - MACHINE learning

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RT Journal Article A1 Das, Ankita A1 Adhikary, Shreya A1 Chowdhury, Amit Roy A1 Barui, Ananya T1 Chirality-induced Lineage Enforcement of Mechanosensitive Mesenchymal Stem Cells Across Germ <highlight>Layer</highlight> <highlight>Boundaries</highlight>. FD Stem Cell Reviews Apr2024, Vol. 20 Issue 3, p755-768, 14p YR 2024 OP 768 VO 20 IS 3 DO 10.1007/s12015-023-10656-5 SP 755 JF Stem Cell Reviews & Reports SN 15508943

Vortex dynamics and boundary layer transition in flow around a rectangular cylinder with different aspect ratios at medium Reynolds number.

Jiang-Hua Li;Bo-Fu Wang;Xiang Qiu;Quan Zhou;Shi-Xiao Fu;Yu-Lu Liu

Academic Journal | Journal of Fluid Mechanics; 3/10/2024, Vol. 982, p1-38, 38p Please log in to see more details

The numerical investigation focuses on the flow patterns around a rectangular cylinder... more

Vortex dynamics and boundary layer transition in flow around a rectangular cylinder with different aspect ratios at medium Reynolds number.

Journal of Fluid Mechanics; 3/10/2024, Vol. 982, p1-38, 38p

The numerical investigation focuses on the flow patterns around a rectangular cylinder with three aspect ratios (L/D = 5, 10, 15) at a Reynolds number of 1000. The study delves into the dynamics of vortices, their associated frequencies, the evolution of the boundary layer and the decay of the wake. Kelvin-Helmholtz (KH) vortices originate from the leading edge (LE) shear layer and transform into hairpin vortices. Specifically, at L/D = 5, three KH vortices merge into a single LE vortex. However, at L/D = 10 and 15, two KH vortices combine to form a LE vortex, with the rapid formation of hairpin vortex packets. A fractional harmonic arises due to feedback from the split LE shear layer moving upstream, triggering interaction with the reverse flow. Trailing edge (TE) vortices shed, creating a Kármán-like street in the wake. The intensity of wake oscillation at L/D = 5 surpasses that in the other two cases. Boundary layer transition occurs after the saturation of disturbance energy for L/D = 10 and 15, but not for L/D = 5. The low-frequency disturbances are selected to generate streaks inside the boundary layer. The TE vortex shedding induces the formation of a favourable pressure gradient, accelerating the flow and fostering boundary layer relaminarization. The self-similarity of the velocity defect is observed in all three wakes, accompanied by the decay of disturbance energy. Importantly, the decrease in the shedding frequency of LE (TE) vortices significantly contributes to the overall decay of disturbance energy. This comprehensive exploration provides insights into complex flow phenomena and their underlying dynamics. [ABSTRACT FROM AUTHOR]

Subject terms:

BOUNDARY layer (Aerodynamics) - TRANSITION flow - REYNOLDS number - VORTEX shedding

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RT Journal Article A1 Jiang-Hua Li A1 Bo-Fu Wang A1 Xiang Qiu A1 Quan Zhou A1 Shi-Xiao Fu A1 Yu-Lu Liu T1 Vortex dynamics and <highlight>boundary</highlight> <highlight>layer</highlight> <highlight>transition</highlight> in flow around a rectangular cylinder with different aspect ratios at medium Reynolds number. FD Journal of Fluid Mechanics; 3/10/2024, Vol. 982, p1-38, 38p YR 2024 OP 38 VO 982 DO 10.1017/jfm.2024.87 SP 1 JF Journal of Fluid Mechanics SN 00221120

Experimental investigation of roughness effects on transition onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis.

Hollis, Brian R.

Book | Experimental investigation of roughness effects on transition onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis.; 01/01/2017 Please log in to see more details

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Experimental investigation of roughness effects on transition onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis.

Experimental investigation of roughness effects on transition onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis.; 01/01/2017

Subject terms:

Boundary layer transition. - Hypersonic wind tunnels. - Surface roughness. - Surface roughness effects. - Thermography.

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RT Journal Article A1 Hollis, Brian R. T1 Experimental investigation of roughness effects on <highlight>transition</highlight> onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis. FD Experimental investigation of roughness effects on transition onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis.; 01/01/2017 YR 2017 JF Experimental investigation of roughness effects on transition onset and turbulent heating augmentation on a hemisphere at Mach 6 and Mach 10 / Brian R. Hollis.

Boundary layer transition of hypersonic flow over a delta wing.

Hongtian Qiu;Mingtao Shi;Yiding Zhu;Cunbiao Lee

Academic Journal | Journal of Fluid Mechanics; 2/10/2024, Vol. 980, p1-37, 37p Please log in to see more details

Cross-flow transition over a delta wing is systematically studied in a Mach 6.5 hypers... more

Boundary layer transition of hypersonic flow over a delta wing.

Journal of Fluid Mechanics; 2/10/2024, Vol. 980, p1-37, 37p

Cross-flow transition over a delta wing is systematically studied in a Mach 6.5 hypersonic wind tunnel, employing the Rayleigh scattering flow visualisation, high-speed schlieren and fast-response pressure sensors. Direct numerical simulations and analysis based on linear stability theory under the same flow conditions are applied to analyse the transition mechanism. Three unstable modes are identified: the travelling cross-flow instabilities, the second mode and the low-frequency waves. It is shown that the travelling cross-flow vortices first appear in the cross-flow region near the leading edge of the model. These vortices can modulate the mean profile of the flow, which benefits the growth of second mode. A phase-locked interaction mechanism transfers energy from the cross-flow instabilities to the high-frequency second mode, leading to amplification at the expense of the cross-flow instability. As the second mode grows to a critical amplitude, it triggers a z-type secondary instability within a similar frequency range, which introduces secondary finger-like structures connecting to the cross-flow vortex. It is further found that the generation of these finger-like structures is related to the expansion and compression of the second mode. These finger vortices further evolve along the streamwise direction into low-frequency waves and corresponding hairpin-like structures that finally trigger turbulence. An interaction mechanism likely exists between the secondary instability and the low-frequency waves, since their phase speeds are approaching each other. These observations of the interaction mechanism are consistent with those of previous studies on hypersonic boundary layers (Zhang et al., Phys. Fluids, vol. 32 (7), 2020, 071702; Li et al., Phys. Fluids, vol. 32 (5), 2020, 051701). [ABSTRACT FROM AUTHOR]

Subject terms:

HYPERSONIC flow - BOUNDARY layer (Aerodynamics) - TRANSITION flow - RAYLEIGH flow - WIND tunnels - CROSS-flow (Aerodynamics) - LYAPUNOV stability

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RT Journal Article A1 Hongtian Qiu A1 Mingtao Shi A1 Yiding Zhu A1 Cunbiao Lee T1 <highlight>Boundary</highlight> <highlight>layer</highlight> <highlight>transition</highlight> of hypersonic flow over a delta wing. FD Journal of Fluid Mechanics; 2/10/2024, Vol. 980, p1-37, 37p YR 2024 OP 37 VO 980 DO 10.1017/jfm.2024.42 SP 1 JF Journal of Fluid Mechanics SN 00221120

A Surrogate-Based Transition Prediction Method for Three-Dimensional Compressible Boundary Layers

Theiss, Alexander;Hein, Stefan;Hirschel, Ernst Heinrich, Founding Editor;Sc...

eBook | New Results in Numerical and Experimental Fluid Mechanics XIV : Contributions to the 23rd STAB/DGLR Symposium, Berlin, Germany, 2022. 154:475-485 Please log in to see more details

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RT Journal Article A1 Theiss, Alexander A1 Hein, Stefan A1 Hirschel, Ernst Heinrich, Founding Editor A1 Schröder, Wolfgang, Series Editor A1 Boersma, Bendiks Jan, Editorial Board Member A1 Fujii, Kozo, Editorial Board Member A1 Haase, Werner, Editorial Board Member A1 Leschziner, Michael A., Editorial Board Member A1 Periaux, Jacques, Editorial Board Member A1 Pirozzoli, Sergio, Editorial Board Member A1 Rizzi, Arthur, Editorial Board Member A1 Roux, Bernard, Editorial Board Member A1 Shokin, Yurii I., Editorial Board Member A1 Lagemann, Esther, Managing Editor A1 Dillmann, Andreas, editor A1 Heller, Gerd, editor A1 Krämer, Ewald, editor A1 Wagner, Claus, editor A1 Weiss, Julien, editor T1 A Surrogate-Based <highlight>Transition</highlight> Prediction Method for Three-Dimensional Compressible <highlight>Boundary</highlight> <highlight>Layers</highlight> FD New Results in Numerical and Experimental Fluid Mechanics XIV : Contributions to the 23rd STAB/DGLR Symposium, Berlin, Germany, 2022. 154:475-485 YR 2024 OP 485 VO 154 DO 10.1007/978-3-031-40482-5_45 SP 475 JF New Results in Numerical and Experimental Fluid Mechanics XIV : Contributions to the 23rd STAB/DGLR Symposium, Berlin, Germany, 2022

Wind Turbine Simulations Using CPU/GPU Heterogeneous Computing

Jung, Yong Su;Baeder, James

Academic Journal | International Journal of Aeronautical and Space Sciences. :1-14 Please log in to see more details

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RT Journal Article A1 Jung, Yong Su A1 Baeder, James T1 Wind Turbine Simulations Using CPU/GPU Heterogeneous Computing FD International Journal of Aeronautical and Space Sciences. :1-14 YR 2023 OP 14 DO 10.1007/s42405-023-00677-2 SP 1 JF International Journal of Aeronautical and Space Sciences SN 2093274X

Gas Kinetic Scheme Coupled with High-Speed Modifications for Hypersonic Transition Flow Simulations.

Li, Chengrui;Zhao, Wenwen;Liu, Hualin;Xue, Youtao;Yang, Yuxin;Chen, Weifang

Academic Journal | Entropy; Feb2024, Vol. 26 Issue 2, p173, 28p Please log in to see more details

The issue of hypersonic boundary layer transition prediction is a critical aerodynamic... more

Gas Kinetic Scheme Coupled with High-Speed Modifications for Hypersonic Transition Flow Simulations.

Entropy; Feb2024, Vol. 26 Issue 2, p173, 28p

The issue of hypersonic boundary layer transition prediction is a critical aerodynamic concern that must be addressed during the aerodynamic design process of high-speed vehicles. In this context, we propose an advanced mesoscopic method that couples the gas kinetic scheme (GKS) with the Langtry–Menter transition model, including its three high-speed modification methods, tailored for accurate predictions of high-speed transition flows. The new method incorporates the turbulent kinetic energy term into the Maxwellian velocity distribution function, and it couples the effects of high-speed modifications on turbulent kinetic energy within the computational framework of the GKS solver. This integration elevates both the transition model and its high-speed enhancements to the mesoscopic level, enhancing the method's predictive capability. The GKS-coupled mesoscopic method is validated through a series of test cases, including supersonic flat plate simulation, multiple hypersonic cone cases, the Hypersonic International Flight Research Experimentation (HIFiRE)-1 flight test, and the HIFiRE-5 case. The computational results obtained from these cases exhibit favorable agreement with experimental data. In comparison with the conventional Godunov method, the new approach encompasses a broader range of physical mechanisms, yielding computational results that closely align with the true physical phenomena and marking a notable elevation in computational fidelity and accuracy. This innovative method potentially satisfies the compelling demand for developing a precise and rapid method for predicting hypersonic boundary layer transition, which can be readily used in engineering applications. [ABSTRACT FROM AUTHOR]

Subject terms:

TRANSITION flow - FLOW simulations - HYPERSONIC flow - BOUNDARY layer (Aerodynamics) - COUPLING schemes - HYPERSONIC aerodynamics

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RT Journal Article A1 Li, Chengrui A1 Zhao, Wenwen A1 Liu, Hualin A1 Xue, Youtao A1 Yang, Yuxin A1 Chen, Weifang T1 Gas Kinetic Scheme Coupled with High-Speed Modifications for Hypersonic <highlight>Transition</highlight> Flow Simulations. FD Entropy; Feb2024, Vol. 26 Issue 2, p173, 28p YR 2024 OP 200 VO 26 IS 2 DO 10.3390/e26020173 SP 173 JF Entropy SN 10994300

Delay of transition using forced damping / Reginald J. Exton.

Exton, Reginald J.

Book | Delay of transition using forced damping / Reginald J. Exton.; 01/01/2014 Please log in to see more details

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Delay of transition using forced damping / Reginald J. Exton.

Delay of transition using forced damping / Reginald J. Exton.; 01/01/2014

Subject terms:

Leading edges. - Boundary layer transition. - Boundary layer stability. - Damping. - Laminar boundary layer.

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RT Journal Article A1 Exton, Reginald J. T1 Delay of <highlight>transition</highlight> using forced damping / Reginald J. Exton. FD Delay of transition using forced damping / Reginald J. Exton.; 01/01/2014 YR 2014 JF Delay of transition using forced damping / Reginald J. Exton.

Exploring flow transition induced by surface-mounted riblets using large eddy simulations.

Jain, Ishita;Sarkar, S.

Academic Journal | Physics of Fluids; Feb2024, Vol. 36 Issue 2, p1-20, 20p Please log in to see more details

A well-resolved large eddy simulation is employed to study the transition of spatially... more

Exploring flow transition induced by surface-mounted riblets using large eddy simulations.

Physics of Fluids; Feb2024, Vol. 36 Issue 2, p1-20, 20p

A well-resolved large eddy simulation is employed to study the transition of spatially developing boundary layer when excited by distributed blade-riblets that are arranged in different configurations: one is two-dimensional spanwise riblets (denoted as R1), and the other being three-dimensional herringbone pattern of alternating converging and diverging riblets (denoted as R2). The inlet Reynolds number based on momentum thickness and freestream velocity is 360. The flow characteristics vary considerably between the two configurations. A transition delay is observed over R1-riblets owing to the recirculation bubbles occupying the entire cavity space between the consecutive riblets. The appearance of T–S waves over R1-riblets is manifested through the modal analysis, which, in concurrence with streaks, leads to the development of Λ-vortices and, thereby, exhibiting characteristics associated with the mixed-mode transition. Contradictorily, the T–S waves are bypassed when subjected to R2-riblets attributed to enhanced spanwise disturbances. The roughness-induced streaks destabilize via a lift-up mechanism and interact with background disturbances, leading to flow transition. Post-transition conditions for self-similarity are met for both configurations, albeit earlier for R2-riblets. [ABSTRACT FROM AUTHOR]

Subject terms:

TRANSITION flow - LARGE eddy simulation models - BOUNDARY layer (Aerodynamics) - MODAL analysis - REYNOLDS number

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RT Journal Article A1 Jain, Ishita A1 Sarkar, S. T1 Exploring flow <highlight>transition</highlight> induced by surface-mounted riblets using large eddy simulations. FD Physics of Fluids; Feb2024, Vol. 36 Issue 2, p1-20, 20p YR 2024 OP 20 VO 36 IS 2 DO 10.1063/5.0186633 SP 1 JF Physics of Fluids SN 10706631

Hydrodynamic effects of the elliptical spacer filament on the flow and mass transfer in a desalination membrane channel.

Li, Xinyu;Hu, Xiao;Zhu, Zuchao;Lin, Yongjie;Lin, Peifeng;Lin, Renyong

Academic Journal | Physics of Fluids; Feb2024, Vol. 36 Issue 2, p1-14, 14p Please log in to see more details

This study numerically investigates the impacts of an elliptical spacer on the flow an... more

Hydrodynamic effects of the elliptical spacer filament on the flow and mass transfer in a desalination membrane channel.

Physics of Fluids; Feb2024, Vol. 36 Issue 2, p1-14, 14p

This study numerically investigates the impacts of an elliptical spacer on the flow and mass transfer within a desalination membrane channel. We consider the effects of the fluid Reynolds number, the elliptical spacer position yin/H, the flow attack angle θ and the aspect ratio B of spacer on the fluid flow, concentration polarization, and permeation flux. Our findings reveal that the elliptical spacers can improve both the mass transfer and permeation flux compared with the traditional circular spacers. Placing the spacer near the membrane surface effectively disrupts the concentration boundary layer, thereby amplifying the local concentration polarization surrounding the spacer. A single recirculation vortex behind the spacer induces numerous large vortices around the membrane, resulting in a significant increment in freshwater production. By changing θ and B, the system's stability can be reduced, potentially leading to a 16.0% increment in permeation flux when compared with the traditional circular spacers. Furthermore, the drag and lift coefficients acting on the elliptical spacer are greater than those of circular spacers, which is the main reason for the transition of flow condition. Our findings provide a reference for the design of the efficient structures in reverse osmosis membranes. [ABSTRACT FROM AUTHOR]

Subject terms:

MASS transfer - TRANSITION flow - BOUNDARY layer (Aerodynamics) - FLUID flow - REYNOLDS number

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RT Journal Article A1 Li, Xinyu A1 Hu, Xiao A1 Zhu, Zuchao A1 Lin, Yongjie A1 Lin, Peifeng A1 Lin, Renyong T1 Hydrodynamic effects of the elliptical spacer filament on the flow and mass transfer in a desalination membrane channel. FD Physics of Fluids; Feb2024, Vol. 36 Issue 2, p1-14, 14p YR 2024 OP 14 VO 36 IS 2 DO 10.1063/5.0177248 SP 1 JF Physics of Fluids SN 10706631

HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry.

Chen, Fang-Jenq

Book | HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry.; 01/01/2010 Please log in to see more details

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HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry.

HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry.; 01/01/2010

Subject terms:

HyBoLT flight experiment. - Aeronautical engineering. - Hypersonic boundary layer. - Transition flight. - Flight control. - Boundary layer transition.

Content provider:

Government Printing Office Catalog

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RT Journal Article A1 Chen, Fang-Jenq T1 HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry. FD HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry.; 01/01/2010 YR 2010 JF HyBoLT flight experiment [electronic resource] / Fang-Jenq (Frank) Chen and Scott A. Berry.

Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others].

Frederick, Michael A.

Book | Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others].; 01/01/2015 Please log in to see more details

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Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others].

Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others].; 01/01/2015

Subject terms:

Boundary layer transition. - Chords (Geometry). - Laminar flow. - Leading edge sweep. - Supersonic airfoils.

Content provider:

Government Printing Office Catalog

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RT Journal Article A1 Frederick, Michael A. T1 Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others]. FD Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others].; 01/01/2015 YR 2015 JF Flight tests of a supersonic natural laminar flow airfoil / Michael A. Frederick [and three others].

Nanoclusters and sol–gel transition in water solutions of rigid-chain polymers.

Bulavin, L. A.;Zabashta, Yu. F.;Vergun, L. Yu.;Alekseev, A. N;Yablochkova, ...

Academic Journal | Molecular Crystals 2023, Vol. 765 Issue 1, p82-89, 8p Please log in to see more details

We describe a mechanism of pre-transition process near the sol-gel transition temperat... more

Nanoclusters and sol–gel transition in water solutions of rigid-chain polymers.

Molecular Crystals 2023, Vol. 765 Issue 1, p82-89, 8p

We describe a mechanism of pre-transition process near the sol-gel transition temperature in the sol-phase of water solutions of rigid-chain polymers. During this process the water boundary layer is disordered, and voids are formed in it. The variation of density of the hydroxypropyl methylcellulose with temperature is measured experimentally for temperatures between 25 and 80 °C. The experiment supports the proposed mechanism. [ABSTRACT FROM AUTHOR]

Subject terms:

POLYMER colloids - POLYMER solutions - TRANSITION temperature - TERRITORIAL waters - WATER boundaries - BOUNDARY layer (Aerodynamics) - POLYMERS - METHYLCELLULOSE

Content provider:

Complementary Index

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RT Journal Article A1 Bulavin, L. A. A1 Zabashta, Yu. F. A1 Vergun, L. Yu. A1 Alekseev, A. N A1 Yablochkova, K. S. A1 Dinzhos, R. V. A1 Fialko, N. M. A1 Lazarenko, M. V. A1 Andrusenko, D. A. A1 Lazarenko, M. M. T1 Nanoclusters and sol–gel <highlight>transition</highlight> in water solutions of rigid-chain polymers. FD Molecular Crystals 2023, Vol. 765 Issue 1, p82-89, 8p YR 2023 OP 89 VO 765 IS 1 DO 10.1080/15421406.2023.2215021 SP 82 JF Molecular Crystals & Liquid Crystals SN 15421406

Outcome of high-speed boundary layer transition workshop at HiSST 2022

Sandham, Neil;Van den Eynde, Jeroen

Academic Journal | CEAS Space Journal: An Official Journal of the Council of European Aerospace Societies. 15(6):989-991 Please log in to see more details

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RT Journal Article A1 Sandham, Neil A1 Van den Eynde, Jeroen T1 Outcome of high-speed <highlight>boundary</highlight> <highlight>layer</highlight> <highlight>transition</highlight> workshop at HiSST 2022 FD CEAS Space Journal: An Official Journal of the Council of European Aerospace Societies. 15(6):989-991 YR 2023 OP 991 VO 15 IS 6 DO 10.1007/s12567-023-00503-1 SP 989 JF CEAS Space Journal: An Official Journal of the Council of European Aerospace Societies SN 18682502

Critical decoupling criterion for dual-incident shock wave/turbulent boundary layer interaction.

Yang, Shu-zi;Xie, Wen-zhong;Sun, Hao-yu

Academic Journal | Physics of Fluids; Jan2024, Vol. 36 Issue 1, p1-12, 12p Please log in to see more details

Interaction zones resulting from the dual-incident shock wave/turbulent boundary layer... more

Critical decoupling criterion for dual-incident shock wave/turbulent boundary layer interaction.

Physics of Fluids; Jan2024, Vol. 36 Issue 1, p1-12, 12p

Interaction zones resulting from the dual-incident shock wave/turbulent boundary layer interactions (D-ISWTBLI) typically exhibit one of two distinct flow patterns: the formation of two isolated small-scale interaction zones following decoupling or the presence of a coupled large-scale interaction zone. This paper investigates the underlying mechanism governing the transition of the flow field of D-ISWTBLI, shifting from a coupled flow pattern to an isolated one. To achieve this, we employ numerical simulations and propose a criterion for determining the critical decoupling condition. Our study commences by presenting an analysis of the time-averaged pressure distribution along-the-wall and the corresponding changes in the characteristic scale of the coupled interaction zone as the spacing between the shock incident points continuously increases. We elucidate the variation mechanism of the characteristic scale by analyzing the flow field. Subsequently, based on the intrinsic relationships among the characteristic scales of the coupled interaction zone in their critical state, we establish a relational expression that links the critical decoupling spacing with the characteristic scales of the interaction zone in the critical state. We then employ numerical simulation data, accounting for key influencing factors such as the intensity ratio of the individual incident shock components comprising the dual-incident shock system, the overall intensity of the dual-incident shock system, and the free-stream conditions to determine the critical decoupling condition. This critical decoupling condition effectively delineates the flow pattern of the interaction zone under various free-stream conditions and shock configurations, a conclusion that is corroborated by published experimental data. [ABSTRACT FROM AUTHOR]

Subject terms:

SHOCK waves - TURBULENT boundary layer - TRANSONIC flow - TRANSITION flow

Content provider:

Complementary Index

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RT Journal Article A1 Yang, Shu-zi A1 Xie, Wen-zhong A1 Sun, Hao-yu T1 Critical decoupling criterion for dual-incident shock wave/turbulent <highlight>boundary</highlight> <highlight>layer</highlight> interaction. FD Physics of Fluids; Jan2024, Vol. 36 Issue 1, p1-12, 12p YR 2024 OP 12 VO 36 IS 1 DO 10.1063/5.0183212 SP 1 JF Physics of Fluids SN 10706631

The Study of Hydrodynamic Processes Occurring on Transition of Sudden Expanding of Hydraulic Section of Plane - Parallel Full Pipe Flow.

Sarukhanyan, Arestak;Vartanyan, Arevshad;Vermishyan, Garnik;Tokmajyan, Vach...

Academic Journal | TEM Journal. Nov2020, Vol. 9 Issue 4, p1494-1501. 8p. Please log in to see more details

The study regarding the regularity of changes in the hydrodynamic processes in the are... more

The Study of Hydrodynamic Processes Occurring on Transition of Sudden Expanding of Hydraulic Section of Plane - Parallel Full Pipe Flow.

TEM Journal. Nov2020, Vol. 9 Issue 4, p1494-1501. 8p.

The study regarding the regularity of changes in the hydrodynamic processes in the area of a sudden expanding in hydraulic section of the planeparallel full pipe flow of the liquid is carried out on the basis of the equations on the boundary layer. A method has been developed for determining the changes in the hydrodynamic parameters of the flow in the transition section which makes it possible to obtain the profile of the distribution of fluid velocities in any cross section of the channel based on the results of deformation of the areas of velocity under common initial and boundary conditions. The hydrodynamic processes occurring on transition of sudden expanding on hydraulic section of plane-parallel full pipe flow are studied in cases when: a) the velocity at any point of the inlet section of the channel is constant; b) the velocity at the inlet section is distributed according to the parabolic law. The calculation results for various values of the coefficient of expansion are given: α=a/h = 0, 3; 0, 5; 0, 7. Based on the results of computer simulation, the course of deformation of the velocity diagram along the length of the transition section was obtained for a constant and parabolic distribution of the velocities of the fluid flowing into the expanded section of the channel. The regularities of pressure distribution along the length of the studied section were also determined. [ABSTRACT FROM AUTHOR]

Subject terms:

BOUNDARY layer equations - TRANSITION flow - EXPANSION of solids - PIPE flow - FLUID flow - DEFORMATIONS (Mechanics)

Content provider:

Academic Search Complete

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RT Journal Article A1 Sarukhanyan, Arestak A1 Vartanyan, Arevshad A1 Vermishyan, Garnik A1 Tokmajyan, Vache T1 The Study of Hydrodynamic Processes Occurring on <highlight>Transition</highlight> of Sudden Expanding of Hydraulic Section of Plane - Parallel Full Pipe Flow. FD TEM Journal. Nov2020, Vol. 9 Issue 4, p1494-1501. 8p. YR 2020 OP 1501 VO 9 IS 4 DO 10.18421/TEM94-23 SP 1494 JF TEM Journal SN 22178309

Statistical investigations of profile error impact on flow and performance of a low-pressure turbine cascade.

Chen, Zeshuai;Luo, Jiaqi;Xia, Zhiheng;Zou, Zhengping;Du, Pengcheng;Liu, Fen...

Academic Journal | Physics of Fluids; Dec2023, Vol. 35 Issue 12, p1-16, 16p Please log in to see more details

Profile error impacts on turbomachinery flow and blade performance have been attractin... more

Statistical investigations of profile error impact on flow and performance of a low-pressure turbine cascade.

Physics of Fluids; Dec2023, Vol. 35 Issue 12, p1-16, 16p

Profile error impacts on turbomachinery flow and blade performance have been attracting widespread attention. In the study, the characteristics of profile error of about one thousand real low-pressure turbine blades are extracted. Sensitivities of total pressure loss coefficient (ζ), outflow angle (β), and Zweifel lift coefficient (zw) of the blade to the basis modes of profile error are calculated. Flow solutions of the blades considering specified basis modes with high sensitivities illustrate that profile error contributes much to the variations of transition onset and flow acceleration on the suction side and flow mixing intensity in the wake. Uncertainty quantification of performance changes is then implemented by the method of moment (MM) using second-order sensitivities. With only 5% computational cost of that by Monte Carlo simulation (MCS), the MM-based statistical results are close to MCS ones with maximum relative error not exceeding 1.07%. The statistical results reveal that the variations of both β and zw are linearly dependent, whereas the variation of ζ is nonlinearly dependent on profile error. As the variation range of profile error increases, the standard deviation and skewness increase, indicating that the performance is more dispersive and the nonlinear dependence of ζ on profile error is intensified. Finally, the MCS flow fields are analyzed. Statistical shear stress near the leading edge and transition onset, statistical boundary layer momentum thickness near transition onset, statistical intermittency near transition onset, and statistical entropy in the wake are more considerable. The impact mechanisms of profile error on turbine flow and performance changes are demonstrated. [ABSTRACT FROM AUTHOR]

Subject terms:

MONTE Carlo method - TURBINE blades - TRANSITION flow - TURBINES - BOUNDARY layer (Aerodynamics)

Content provider:

Complementary Index

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RT Journal Article A1 Chen, Zeshuai A1 Luo, Jiaqi A1 Xia, Zhiheng A1 Zou, Zhengping A1 Du, Pengcheng A1 Liu, Feng T1 Statistical investigations of profile error impact on flow and performance of a low-pressure turbine cascade. FD Physics of Fluids; Dec2023, Vol. 35 Issue 12, p1-16, 16p YR 2023 OP 16 VO 35 IS 12 DO 10.1063/5.0179970 SP 1 JF Physics of Fluids SN 10706631

Investigation of machining flaw of transverse micro-grooves on the control effect of boundary layer instability

Liu, Yong;Long-Guo, Qi;Hua-Tu, Guo;Yang, Qiang;Xu-Yuan, Xian;Bing-Wan, Bing

Conference | 2021 7th International Conference on Mechanical Engineering and Automation Science (ICMEAS) ICMEAS Mechanical Engineering and Automation Science (ICMEAS), 2021 7th International Conference on. :132-139 Oct, 2021 Please log in to see more details

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RT Journal Article A1 Liu, Yong A1 Long-Guo, Qi A1 Hua-Tu, Guo A1 Yang, Qiang A1 Xu-Yuan, Xian A1 Bing-Wan, Bing T1 Investigation of machining flaw of transverse micro-grooves on the control effect of <highlight>boundary</highlight> <highlight>layer</highlight> instability FD 2021 7th International Conference on Mechanical Engineering and Automation Science (ICMEAS) ICMEAS Mechanical Engineering and Automation Science (ICMEAS), 2021 7th International Conference on. :132-139 Oct, 2021 YR 2021 OP 139 DO 10.1109/ICMEAS54189.2021.00035 SP 132 JF 2021 7th International Conference on Mechanical Engineering and Automation Science (ICMEAS), Mechanical Engineering and Automation Science (ICMEAS), 2021 7th International Conference on, ICMEAS

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