Turbulent Reduction in a Wind Tunnel Using Trip Strip

Volume 1 ◽  
2004 ◽  
Author(s):  
Mohammad Reza Soltani ◽  
Mojtaba Dehghan Manshadi ◽  
Mohammad Javad Mirabdollahi
Keyword(s):  
Experimental Study ◽  
Wind Tunnel ◽  
Test Section ◽  
Velocity Profiles ◽  
Turbulent Intensity ◽  
Tunnel Wall ◽  
Low Speed ◽  
Flow Quality

In this investigation an intensive experimental study was conducted to study the flow quality in a test section of a low speed, V∞ = 10–100, closed return wind tunnel. An interesting result was obtained when a trip strip, a guitar wire with D = 1.14mm, was installed near the end of the contraction region. Addition of this trip wire resulted in a turbulent reduction almost at all speed ranges along the entire test section. Further, it smoothness the variation of turbulent intensity along the test section too. Velocity profiles along the tunnel wall at various speeds using a rake were measured with and without the trip wire. In addition, pressure contours at different location of the test section was measured too.

scholarly journals An Experimental Study of Test Section Velocity Calibration for Low-Speed Wind Tunnel

2012 ◽  
Vol 40 (3) ◽  
pp. 230-236 ◽  
Author(s):  
Se-Yoon Oh ◽  
Jong-Geon Lee ◽  
Sung-Cheol Kim ◽  
Sang-Ho Kim ◽  
Seung-Ki Ahn
Keyword(s):  
Experimental Study ◽  
Wind Tunnel ◽  
Test Section ◽  
Low Speed ◽  
Velocity Calibration ◽  
Low Speed Wind Tunnel

Control of separation in the concave portion of contraction to improve the flow quality

2009 ◽  
Vol 113 (1141) ◽  
pp. 177-182 ◽  
Author(s):  
K. Ghorbanian ◽  
M. R. Soltani ◽  
M. D. Manshadi ◽  
M. Mirzaei
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Turbulence Intensity ◽  
Test Section ◽  
Adverse Pressure Gradient ◽  
Wind Tunnel Experiments ◽  
Free Stream Turbulence ◽  
Static Pressure Distribution ◽  
Subsonic Wind Tunnel ◽  
Flow Quality

AbstractSubsonic wind tunnel experiments were conducted to study the effect of forced transition on the pressure distribution in the concave portion of contraction. Further more, the effect of early transition on the turbulence level in the test section of the wind tunnel is studied. Measurements were performed by installing several trip strips at two different positions in the concave portion of the contraction. The results show that installation of the trip strips, have significant effects on both turbulence intensity and on the pressure distribution. The reduction in the free stream turbulence as well as the wall static pressure distribution varied significantly with the location of the trip strip. The results confirm the significant impact of the tripped boundary layer on the control of adverse pressure gradient. The trip strip atX/L= 0.115 improves pressure distribution in contraction and reduces turbulence intensity in the test section, considerably.

Numerical and experimental investigations on the reduction of wind tunnel wall interference by means of adaptive slots

2001 ◽  
Vol 105 (1052) ◽  
pp. 571-580 ◽  
Author(s):  
O. Meyer ◽  
W. Nitsche ◽  
I. Futterer
Keyword(s):  
Wind Tunnel ◽  
Test Section ◽  
Wind Tunnels ◽  
Experimental Investigations ◽  
Reference Case ◽  
Tunnel Wall ◽  
Promising Alternative ◽  
Model Flow ◽  
Flexible Walls ◽  
Basic Studies

Abstract The flow in many wind tunnel experiments is affected by the presence of test section walls. The resulting interference can be minimised by correcting the measured model pressures, or by influencing the model flow directly with the use of ventilated or adaptive test section walls. The objective behind the latter technique is to guide the flow in the test section to achieve low interference (i.e. free flow) condition at the model. The most successful technique of flexible, adaptive walls is still restricted to small research wind tunnels due to its mechanical complexity. However, a very promising alternative is the use of adaptive slots in the test section walls. This concept combines the method of passive slotted walls, as they are already implemented in many large wind tunnels, and flexible walls. Additionally, this technique presents the opportunity of full 3D adaptations because the slots can be situated in all four test section walls. This paper presents preliminary experimental results and the latest numerical calculations on the effectiveness of adaptive slots. The experiments were conducted under high subsonic flow conditions in the new slotted test section of the transonic wind tunnel at TU Berlin’s Aeronautical Institute (ILR). The numerical results presented are focussed on the 2D slot adaptation of a 2D-model (CAST7 aerofoil) and the 3D slot adaptation of a body of revolution (3D-ETB). In addition, basic studies were made of the flows associated with a single slot on one wall and a bump on the other. The numerical and the first experimental investigations have shown the potential of adaptive slots to reduce wall interferences effectively. The adaptation accuracy of the investigated slot configurations deviated not more than 3% from the reference case (2D-wall adaptation).

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