scholarly journals Nonlinearity Identification and Flow Control for Low-Reynolds Number Aerodynamics with Unsteady Free-Stream

2012 ◽  
Author(s):  
Young-Chang Cho ◽  
Wei Shyy
Keyword(s):  
Reynolds Number ◽  
Flow Control ◽  
Free Stream ◽  
Low Reynolds Number ◽  
Low Reynolds

scholarly journals Passive flow control strategies for low Reynolds number airfoils

2020 ◽  
Vol 954 ◽  
pp. 012002
Author(s):  
T Rajesh Senthil Kumar ◽  
Mohini Priya Kolluri ◽  
V R Gopal Subramaniyan ◽  
A D Sripathi
Keyword(s):  
Reynolds Number ◽  
Flow Control ◽  
Control Strategies ◽  
Low Reynolds Number ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Low Reynolds

Low Reynolds Number Laminar Airfoil with Active Flow Control

2010 ◽  
Author(s):  
Michael Thake ◽  
Nathan Packard ◽  
Carlos Bonilla ◽  
Jeffrey Bons
Keyword(s):  
Reynolds Number ◽  
Flow Control ◽  
Low Reynolds Number ◽  
Active Flow Control ◽  
Low Reynolds ◽  
Active Flow

Numerical investigation of the role of free-stream turbulence in boundary-layer separation

2016 ◽  
Vol 801 ◽  
pp. 289-321 ◽  
Author(s):  
Wolfgang Balzer ◽  
H. F. Fasel
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Shear Layer ◽  
Free Stream ◽  
Hydrodynamic Instability ◽  
Low Reynolds Number ◽  
Transition To Turbulence ◽  
Laminar Separation ◽  
Free Stream Turbulence ◽  
Low Reynolds

The aerodynamic performance of lifting surfaces operating at low Reynolds number conditions is impaired by laminar separation. In most cases, transition to turbulence occurs in the separated shear layer as a result of a series of strong hydrodynamic instability mechanisms. Although the understanding of these mechanisms has been significantly advanced over the past decades, key questions remain unanswered about the influence of external factors such as free-stream turbulence (FST) and others on transition and separation. The present study is driven by the need for more accurate predictions of separation and transition phenomena in ‘real world’ applications, where elevated levels of FST can play a significant role (e.g. turbomachinery). Numerical investigations have become an integral part in the effort to enhance our understanding of the intricate interactions between separation and transition. Due to the development of advanced numerical methods and the increase in the performance of supercomputers with parallel architecture, it has become feasible for low Reynolds number application ($O(10^{5})$) to carry out direct numerical simulations (DNS) such that all relevant spatial and temporal scales are resolved without the use of turbulence modelling. Because the employed high-order accurate DNS are characterized by very low levels of background noise, they lend themselves to transition research where the amplification of small disturbances, sometimes even growing from numerical round-off, can be examined in great detail. When comparing results from DNS and experiment, however, it is beneficial, if not necessary, to increase the background disturbance levels in the DNS to levels that are typical for the experiment. For the current work, a numerical model that emulates a realistic free-stream turbulent environment was adapted and implemented into an existing Navier–Stokes code based on a vorticity–velocity formulation. The role FST plays in the transition process was then investigated for a laminar separation bubble forming on a flat plate. FST was shown to cause the formation of the well-known Klebanoff mode that is represented by streamwise-elongated streaks inside the boundary layer. Increasing the FST levels led to accelerated transition, a reduction in bubble size and better agreement with the experiments. Moreover, the stage of linear disturbance growth due to the inviscid shear-layer instability was found to not be ‘bypassed’.

Heat Flow Control at Low Reynolds Number Utilizing pH-Sensitive Viscoelastic Properties of a Surfactant Solution

2020 ◽  
Vol 2020.95 (0) ◽  
pp. 07_715
Author(s):  
Naoya KOMODA ◽  
Reiko KURIYAMA ◽  
Kazuya TATSUMI ◽  
Kazuyoshi NAKABE
Keyword(s):  
Reynolds Number ◽  
Heat Flow ◽  
Flow Control ◽  
Viscoelastic Properties ◽  
Low Reynolds Number ◽  
Surfactant Solution ◽  
Ph Sensitive ◽  
Low Reynolds

Flow control of the wake vortex street of a circular cylinder by using a traveling wave wall at low Reynolds number

2017 ◽  
Vol 145 ◽  
pp. 52-67 ◽  
Author(s):  
Feng Xu ◽  
Wen-Li Chen ◽  
Wei-Feng Bai ◽  
Yi-Qing Xiao ◽  
Jin-Ping Ou
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Flow Control ◽  
Traveling Wave ◽  
Low Reynolds Number ◽  
Vortex Street ◽  
Wake Vortex ◽  
Low Reynolds

scholarly journals Theoretical Analysis of Supersonic Low Reynolds Number Flow Control Technique Based on Flow Mixing

2020 ◽  
Vol 751 ◽  
pp. 012009
Author(s):  
Xu Dachuan ◽  
Ren Zebin ◽  
Chen Zhiqiang ◽  
Wang Haifeng ◽  
Guo Longde
Keyword(s):  
Reynolds Number ◽  
Theoretical Analysis ◽  
Flow Control ◽  
Low Reynolds Number ◽  
Control Technique ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Flow Mixing ◽  
Number Flow ◽  
Low Reynolds
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