Analysis of boundary layers on perforated walls of transonic wind tunnels

1981 ◽  
Vol 18 (6) ◽  
pp. 469-473 ◽  
Author(s):  
Y.Y. Chan
Keyword(s):  
Boundary Layers ◽  
Wind Tunnels

Decreasing the Side Wall Contamination in Wind Tunnels

1983 ◽  
Vol 105 (4) ◽  
pp. 435-438 ◽  
Author(s):  
T. Motohashi ◽  
R. F. Blackwelder
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Boundary Layers ◽  
Laminar Boundary Layer ◽  
Three Dimensional ◽  
Side Wall ◽  
Wind Tunnels ◽  
Turbulent Fluid ◽  
Side Walls ◽  
Suction Slot

To study boundary layers in the transitional Reynolds number regime, the useful spanwise and streamwise extent of wind tunnels is often limited by turbulent fluid emanating from the side walls. Some or all of the turbulent fluid can be removed by sucking fluid out at the corners, as suggested by Amini [1]. It is shown that by optimizing the suction slot width, the side wall contamination can be dramatically decreased without a concomitant three-dimensional distortion of the laminar boundary layer.

Boundary Layer and Loss Measurements on the Rotor of an Axial-Flow Turbine

1984 ◽  
Vol 106 (2) ◽  
pp. 391-399 ◽  
Author(s):  
H. P. Hodson
Keyword(s):  
Boundary Layers ◽  
Large Scale ◽  
Axial Flow ◽  
Turbine Rotor ◽  
Wind Tunnels ◽  
Shear Stresses ◽  
Surface Shear ◽  
Laminar Boundary Layers ◽  
Rotor Stator Interaction ◽  
Profile Loss

The aerodynamic efficiency of an axial-flow turbine is significantly less than that predicted by measurements made on equivalent cascades which operate with steady inflow. This difference in efficiencies is strongly dependent upon the rotor-stator axial spacing. An experimental investigation of the rotor-stator interaction has therefore been conducted using a large-scale, low-speed turbine. The blade profile loss and surface shear stresses are presented for the midspan of the rotor and for a rectilinear cascade of identical geometry. Both wind tunnels were operated at a Reynolds number of 3.15 × 105. The turbine rotor midspan profile loss was approximately 50 percent higher than that of the rectilinear cascade. The shear stress measurements indicate that as a stator wake is connected through a rotor passage, the laminar boundary layers undergo transition in the vicinity of the wake. The 50 percent increase in loss is due to the time-dependent transitional nature of the boundary layers.

scholarly journals Nozzle Geometry Effects on Corner Boundary Layers in Supersonic Wind Tunnels

AIAA Journal ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 3620-3623 ◽  
Author(s):  
Kshitij Sabnis ◽  
Holger Babinsky
Keyword(s):  
Boundary Layers ◽  
Wind Tunnels ◽  
Nozzle Geometry ◽  
Geometry Effects

The spanwise perturbation of two-dimensional boundary layers

1966 ◽  
Vol 24 (1) ◽  
pp. 153-164 ◽  
Author(s):  
S. C. Crow
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Plate Boundary ◽  
Wind Tunnels ◽  
Two Dimensional ◽  
Surface Shear ◽  
Flow Reynolds Number ◽  
Two Dimensional Flow ◽  
Dimensional Boundary ◽  
Small Periodic

Large spanwise variations of boundary-layer thickness and surface shear have been found recently in wind tunnels designed to maintain two-dimensional flow. Bradshaw (1965) argues that these variations are caused by minute deflexions in the free-stream flow rather than by any intrinsic instability of the boundary layers. This paper is a study of the effect of a small, periodic transverse flow on a flat-plate boundary layer. The perturbation flow Reynolds number is assumed to be O(1) as it is in the experiments.

Wind-tunnel simulation of the atmospheric boundary layer: a report on Euromech 50

1975 ◽  
Vol 70 (3) ◽  
pp. 543-559 ◽  
Author(s):  
J. C. R. Hunt ◽  
H. Fernholz
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Atmospheric Boundary Layer ◽  
Boundary Layers ◽  
Wind Tunnels ◽  
Atmospheric Conditions ◽  
Atmospheric Boundary Layers ◽  
Future Developments ◽  
Wind Tunnel Simulation

The 50th Euromech Colloquium, on wind-tunnel simulation of the atmospheric boundary layer, was held in Berlin from 23–25 September 1974. Thirty-eight participants from eleven countries were present. Papers were presented describing and analysing different methods of simulation of neutral, stable and unstable atmospheric conditions in various types of wind tunnel. Numerous applications of wind-tunnel simulations were described or mentioned in the papers and the discussion sessions. Some conclusions about the validity, the techniques, the limitations and future developments of wind-tunnel simulations were reached in discussion. Tables are presented in appendix A listing the institutes in Europe and the U.S.A. of actual or invited participants where wind tunnels are used for simulation work; also listed are the characteristics of the wind tunnels and relevant measurements of the simulated atmospheric boundary layers, to enable comparisons to be made between different techniques.

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