Mechanical Engineering (MNE) Seminar by Dr. Wen Wu
When: Friday,
October 6, 2023
2:30 PM
-
3:30 PM
Where: > See description for location
Description: Mechanical Engineering (MNE) SEMINAR
DATE:
October 6, 2023
TIME:
2:30 p.m. - 3:30 p.m.
ZOOM:
https://umassd.zoom.us/j/91640406955?pwd=eklBZWVDOXVDa2VwUFMra1kwNWhjdz09
(Passcode: 500)
SPEAKER:
Dr. Wen Wu, Assistant Professor
Mechanical Engineering, General Engineering, University of Mississippi
TOPIC:
Roughness Effects in Non-Equilibrium Turbulent Flows
ABSTRACT:
Extensive studies have been performed in the realm of surface roughness in the areas of fluid dynamics, marine science, biomedical engineering, etc. The core of existing research is parameterizing the effects of roughness by an analogy to the smooth-wall logarithmic profile. Deviations from the canonical turbulent flow, however, challenge the validity of the law of the wall, thus imposing uncertainty in utilizing the roughness corrections developed for canonical turbulent boundary layers (TBL). In this talk, findings from several numerical investigations of roughness effects in non-equilibrium turbulent flows are discussed. A) Despite that roughness is often considered a mixing enhancer at the wall, it promotes the separation of TBL induced by an adverse pressure gradient rather than delaying it. B) DNS of channel flow subjected to spanwise rotation was performed, comparing cases with smooth and rough walls. The destabilizing effect of roughness counteracts the stabilizing effect of rotation and prevents flow from reaching a quasi-laminar state. The wake field, i.e., the spatial variation of the averaged quantities around the roughness elements, affects the shear stress budget most significantly. C) DNS of a pulsatile channel flow over roughness further highlights the critical role of the local flow around roughness elements in modifying the near-wall turbulence.
BIO:
Dr. Wen Wu is an Assistant Professor at the University of Mississippi (UM) since 2020. He completed his Ph.D. degree at Queen's University, Canada, and conducted his postdoctoral research at Johns Hopkins University. He also served as a Visiting Assistant Professor at the Center for Turbulence Research at Stanford during the summer of 2022 and 2023. Dr. Wu combines high-fidelity simulations and theoretical analysis for his research, with an emphasis on the multiscale and non-equilibrium aspects of turbulence. His recent research has focused on vortex-dominated flows, flow separation, and turbulence-surface structure interactions.
For more information please contact Dr. Hangjian Ling, MNE Seminar Coordinator (hling1@umassd.edu).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE students (BS and MS) are encouraged to attend. EAS students are also encouraged to attend.
DATE:
October 6, 2023
TIME:
2:30 p.m. - 3:30 p.m.
ZOOM:
https://umassd.zoom.us/j/91640406955?pwd=eklBZWVDOXVDa2VwUFMra1kwNWhjdz09
(Passcode: 500)
SPEAKER:
Dr. Wen Wu, Assistant Professor
Mechanical Engineering, General Engineering, University of Mississippi
TOPIC:
Roughness Effects in Non-Equilibrium Turbulent Flows
ABSTRACT:
Extensive studies have been performed in the realm of surface roughness in the areas of fluid dynamics, marine science, biomedical engineering, etc. The core of existing research is parameterizing the effects of roughness by an analogy to the smooth-wall logarithmic profile. Deviations from the canonical turbulent flow, however, challenge the validity of the law of the wall, thus imposing uncertainty in utilizing the roughness corrections developed for canonical turbulent boundary layers (TBL). In this talk, findings from several numerical investigations of roughness effects in non-equilibrium turbulent flows are discussed. A) Despite that roughness is often considered a mixing enhancer at the wall, it promotes the separation of TBL induced by an adverse pressure gradient rather than delaying it. B) DNS of channel flow subjected to spanwise rotation was performed, comparing cases with smooth and rough walls. The destabilizing effect of roughness counteracts the stabilizing effect of rotation and prevents flow from reaching a quasi-laminar state. The wake field, i.e., the spatial variation of the averaged quantities around the roughness elements, affects the shear stress budget most significantly. C) DNS of a pulsatile channel flow over roughness further highlights the critical role of the local flow around roughness elements in modifying the near-wall turbulence.
BIO:
Dr. Wen Wu is an Assistant Professor at the University of Mississippi (UM) since 2020. He completed his Ph.D. degree at Queen's University, Canada, and conducted his postdoctoral research at Johns Hopkins University. He also served as a Visiting Assistant Professor at the Center for Turbulence Research at Stanford during the summer of 2022 and 2023. Dr. Wu combines high-fidelity simulations and theoretical analysis for his research, with an emphasis on the multiscale and non-equilibrium aspects of turbulence. His recent research has focused on vortex-dominated flows, flow separation, and turbulence-surface structure interactions.
For more information please contact Dr. Hangjian Ling, MNE Seminar Coordinator (hling1@umassd.edu).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE students (BS and MS) are encouraged to attend. EAS students are also encouraged to attend.
Topical Areas: Faculty, General Public, Staff and Administrators, Students, Students, Graduate, Students, Undergraduate, University Community, College of Engineering, Mechanical Engineering, Lectures and Seminars