No video

Vortex shedding and its control | Prof. S. D. Sharma | 2017

  Рет қаралды 16,971

IIT Gandhinagar

IIT Gandhinagar

Күн бұрын

Periodic vortex shedding, also known as Karman vortex shedding, is a common phenomenon that occurs in the wake of a nominally two dimensional bluff body due to interaction between two separated shears layers from opposite sides. We have employed numerous methods, both active and passive, to suppress this alternate vortex shedding in order to alleviate its detrimental effects such as high form drag, flow induced vibration and noise. In active control method, only one of the shear layers at the trailing edge of a blunt based aerofoil was either sucked in or tangentially blown just before the separation. With increasing strength of the suction and blowing, a complete suppression of the vortex shedding could be achieved. The efficacy of the steady blowing technique was further significantly improved by making it pulsating. The pulsating blowing was applied in open-loop mode with two control parameters - blowing strength and pulsating frequency. For the frequency of blowing being twice the unforced vortex shedding frequency and the active phase of the cycle being just 20%, not only a complete suppression of the vortex shedding was achieved but also the wake was found to gain momentum. In passive control method, the spanwise vortex dislocation was introduced by certain geometric cutouts provided at the model trailing edge. The serration shapes were found to introduce strong streamwise vortices in pairs of either co-rotating or contra-rotating by choice. The regular vortex shedding was effectively suppressed resulting in about 34% reduction in the form drag. Moreover, the pairs of contra-rotating vortices were found to generate lift even at zero angle of incidence due to wake vectoring (downwash) effect. Further, following the technique of active control, only one of the separated shear layer was cancelled by placing a short plate at an angle in its path which resulted in a complete suppression of the vortex shedding. Periodic vortex shedding, also known as Karman vortex shedding, is a common phenomenon that occurs in the wake of a nominally two dimensional bluff body due to interaction between two separated shears layers from opposite sides. We have employed numerous methods, both active and passive, to suppress this alternate vortex shedding in order to alleviate its detrimental effects such as high form drag, flow induced vibration and noise. In active control method, only one of the shear layers at the trailing edge of a blunt based aerofoil was either sucked in or tangentially blown just before the separation. With increasing strength of the suction and blowing, a complete suppression of the vortex shedding could be achieved. The efficacy of the steady blowing technique was further significantly improved by making it pulsating. The pulsating blowing was applied in open-loop mode with two control parameters - blowing strength and pulsating frequency. For the frequency of blowing being twice the unforced vortex shedding frequency and the active phase of the cycle being just 20%, not only a complete suppression of the vortex shedding was achieved but also the wake was found to gain momentum. In passive control method, the spanwise vortex dislocation was introduced by certain geometric cutouts provided at the model trailing edge. The serration shapes were found to introduce strong streamwise vortices in pairs of either co-rotating or contra-rotating by choice. The regular vortex shedding was effectively suppressed resulting in about 34% reduction in the form drag. Moreover, the pairs of contra-rotating vortices were found to generate lift even at zero angle of incidence due to wake vectoring (downwash) effect. Further, following the technique of active control, only one of the separated shear layer was cancelled by placing a short plate at an angle in its path which resulted in a complete suppression of the vortex shedding.

Пікірлер: 12
@srijitapaul5080
@srijitapaul5080 4 жыл бұрын
Not fair, Mathematics shouldn't be removed.
@MalefuNhlapo-tt2yw
@MalefuNhlapo-tt2yw Жыл бұрын
Me watching in 2023 from south Africa 🇿🇦🇿🇦 thank you Sir
@harshalssingh3689
@harshalssingh3689 2 жыл бұрын
Freaking amazing lecture sir. Thank you so much.
@railwayaspirant424
@railwayaspirant424 4 жыл бұрын
Excellent lecture
@DharambirPoddar
@DharambirPoddar 4 жыл бұрын
excellent !!!!!!!!
@xwdoctor4420
@xwdoctor4420 5 жыл бұрын
thank you
@manoranjansrinivasan2702
@manoranjansrinivasan2702 5 жыл бұрын
Poor camera work... But good content..
@vallurusailakshminrusimhap2873
@vallurusailakshminrusimhap2873 3 жыл бұрын
Can anyone help me with the difference between vortex-induced vibration and flutter phenomenon?
@kohinoor9070
@kohinoor9070 Жыл бұрын
18:53
@deepbhatt2254
@deepbhatt2254 4 жыл бұрын
where can i get this presentation?
@Jatinderchahal19
@Jatinderchahal19 3 жыл бұрын
did you get??
@deepbhatt2254
@deepbhatt2254 3 жыл бұрын
@@Jatinderchahal19 no i didn't
Andrei Metrikine/NONLINEAR DYNAMICS OF OFFSHORE STRUCTURES/ICSV24
51:09
Institute of Acoustics
Рет қаралды 8 М.
Doug McLean | Common Misconceptions in Aerodynamics
48:26
Michigan Engineering
Рет қаралды 723 М.
ROLLING DOWN
00:20
Natan por Aí
Рет қаралды 10 МЛН
КАКУЮ ДВЕРЬ ВЫБРАТЬ? 😂 #Shorts
00:45
НУБАСТЕР
Рет қаралды 3,2 МЛН
Meet the one boy from the Ronaldo edit in India
00:30
Younes Zarou
Рет қаралды 16 МЛН
Vortex Shedding - Smarter Every Day 23
4:24
SmarterEveryDay
Рет қаралды 399 М.
Blaze of Steel: Explosive Chemistry - with Andrew Szydlo
1:56:43
The Royal Institution
Рет қаралды 4 МЛН
The Fluid Flow around an Infinite Cylinder | Deep Dive Maths
16:54
Jeffrey Chasnov
Рет қаралды 16 М.
Introduction to Vibration and Dynamics
1:03:18
nCode Software
Рет қаралды 91 М.
Von Karman Street Vortex Suppression Study
4:24
olliewest
Рет қаралды 29 М.
Internet is going wild over this problem
9:12
MindYourDecisions
Рет қаралды 103 М.
Conversation: Salam, Sciama, Witten and Budinich
49:00
Int'l Centre for Theoretical Physics
Рет қаралды 383 М.
Insights on Vortex-induced Vibrations from Forced Motion Experiment Data - PMEC Seminar
1:04:29
ROLLING DOWN
00:20
Natan por Aí
Рет қаралды 10 МЛН