Wind-tunnel experiments and separation control of a NACA4412 with 25○sweep at high Reynolds numbers

2022 ◽  
Author(s):  
Pierre-Yves Passaggia ◽  
Guillermo Lopez Quesada ◽  
Stéphane Loyer ◽  
Lucien Baldas ◽  
Jean-Christophe Robinet ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Reynolds Numbers ◽  
Separation Control ◽  
Wind Tunnel Experiments ◽  
High Reynolds Numbers ◽  
High Reynolds

Predicting Spar VIM Using CFD

2008 ◽  
Author(s):  
Samuel Holmes
Keyword(s):  
Wind Tunnel ◽  
Recent Work ◽  
Reynolds Numbers ◽  
Scale Model ◽  
Small Scale ◽  
Wind Tunnel Experiments ◽  
High Reynolds Numbers ◽  
Induced Motion ◽  
High Reynolds ◽  
Very High

Recent work toward predicting spar vortex induced motion (VIM) with computational fluid dynamics (CFD) suggests that such simulations can anticipate many aspects of spar response and thus supplement tow tank experiments and other design methods. However, the results also highlight a number of challenges as well. The spar VIM problem is characterized by very high Reynolds numbers, geometric complexity including the presence of numerous external appendages and the presence of very rough surfaces. In this paper, we first review recent work on spar VIM where CFD was used to simulate tow tank experiments. This work suggests that CFD methods give good results in most cases but also points to some exceptions. In particular, in simulations of small scale vortex induced motion tests of spars, good agreement between analysis and experiments is usually obtained when the flow separates from the spar hull at the strakes. The CFD simulations are sometimes less successful at predicted VIM when flow separation occurs at the spar hull. We then examine our own recent practice in simulating tow tank experiments with CFD with the objective of finding possible modeling deficiencies. The focus is on the resolution of the large eddies in the wake which most influence the fluctuating loads on the spar, but we are also concerned with the use of wall functions to model the boundary layer. All of the calculations use detached eddy simulation (DES). In order to test the method, we make use of wind tunnel experiments at on a fixed truncated cylinder without strakes. The wind tunnel experiments are performed at Reynolds numbers (Re) that are about the same as those used in scale model spar VIM experiments. Wake particle image velocimetry (PIV) and other data from wind tunnel experiments published in the open literature are used for comparison. The comparisons are used to examine requirements for grid resolution in the wake. Finally, it is suggested that specific wind tunnel experiments might be used to gather needed data on the effects of rough walls and appendages at very high Reynolds numbers.

An Intermittent High-Reynolds-Number Wind Tunnel

1977 ◽  
Vol 28 (4) ◽  
pp. 259-264 ◽  
Author(s):  
J L Stollery ◽  
A V Murthy
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
High Reynolds Number ◽  
Reynolds Numbers ◽  
Simple Method ◽  
High Reynolds Numbers ◽  
Reservoir Conditions ◽  
High Reynolds ◽  
Cryogenic Wind Tunnel ◽  
Performance Estimates

SummaryThe paper suggests a simple method of generating intermittent reservoir conditions for an intermittent, cryogenic wind tunnel. Approximate performance estimates are given and it is recommended that further studies be made because this type of tunnel could be valuable in increasing the opportunities for research at high Reynolds numbers.

scholarly journals Wind Tunnel Tests of Wind Turbine Airfoils at High Reynolds Numbers

2014 ◽  
Vol 524 ◽  
pp. 012012 ◽  
Author(s):  
E Llorente ◽  
A Gorostidi ◽  
M Jacobs ◽  
W A Timmer ◽  
X Munduate ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Reynolds Numbers ◽  
Wind Tunnel Tests ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
Turbine Airfoils

scholarly journals Flow Structure behind a Wing at High Reynolds Numbers

2018 ◽  
Vol 180 ◽  
pp. 02111 ◽  
Author(s):  
Václav Uruba ◽  
Zdeněk Pátek ◽  
Pavel Procházka ◽  
Vladislav Skála ◽  
David Zacho ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flow Structure ◽  
Reynolds Numbers ◽  
Streamwise Direction ◽  
Vortical Structures ◽  
High Reynolds Numbers ◽  
Piv Measurement ◽  
High Reynolds

The stereo PIV measurement were performed behind a wing in the plane perpendicular to the flow to study the vortical structures oriented in the streamwise direction, which take place both in suction and pressure sides of the wing. The Reynolds numbers during the experiments in the 3 m wind tunnel range from 0.5 million up to 1.5 million.

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