Wind tunnel wall influence considering two-dimensional high-lift configurations

1986 ◽  
Vol 23 (2) ◽  
pp. 118-125
Author(s):  
T. E. Labrujere ◽  
R. A. Maarsingh ◽  
J. Smith
Keyword(s):  
Wind Tunnel ◽  
Two Dimensional ◽  
Tunnel Wall ◽  
High Lift

Numerical Comparison of Dynamic Stall for Two-Dimensional Airfoils and an Airfoil Model in the DNW–TWG

2012 ◽  
Vol 57 (4) ◽  
pp. 1-13 ◽  
Author(s):  
A. Klein ◽  
Th. Lutz ◽  
E. Krämer ◽  
K. Richter ◽  
A.D. Gardner ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Dynamic Stall ◽  
Numerical Comparison ◽  
Two Dimensional ◽  
Tunnel Wall ◽  
Unsteady Separation ◽  
Wide Range ◽  
Effective Angle ◽  
Unsteady Characteristics ◽  
Dynamics Simulations

The airfoil sections of helicopter rotors experience a wide range of flow conditions in forward flight from transonic flow on the advancing blade to subsonic flow and high angles of attack on the retreating blade. Most notably, the dynamic stall phenomenon has been a research topic for decades and various models have been introduced to predict the unsteady characteristics of the rotor blade undergoing unsteady separation. The objective of the present paper is to compare two-dimensional (2D) dynamic stall computations, suitable for airfoil design studies considering unsteady characteristics, with computational fluid dynamics simulations of the wind tunnel environment taking into account three dimensionality and wall effects. Differences between experiment and 2D computations can be partly attributed to sidewall effects, which alter the effective angle of attack at the midsection pressure measurement plane. To gain more insight into these effects, investigations are presented, which show the wind tunnel wall boundary layers and separation effects at the sidewall–airfoil junction.

Research of Measurement Method of Two Dimensional Configuration Drag Test in Wind Tunnel in Case of High Lift

2011 ◽  
Vol 301-303 ◽  
pp. 671-676
Author(s):  
Yu Qin Jiao ◽  
Xi Ping Chen ◽  
Zhen Li Zhi
Keyword(s):  
Wind Tunnel ◽  
Stokes Equations ◽  
Wind Tunnel Test ◽  
Flow Characteristics ◽  
Aerodynamic Performance ◽  
Wake Flow ◽  
Navier Stokes ◽  
Two Dimensional ◽  
High Lift ◽  
Navier Stokes Equations

Computational fluid dynamics and wind tunnel test are two main technical means to examine the aerodynamic performance of airfoil and two-dimensional(2-D) configuration. Two dimensional wind tunnel tests use commonly wake flow field measurement to integrate for drag of airfoil or two-dimensional configuration, but the integral formulas are based on certain assumptions and of certain bounds of application. In this paper, based on Navier-Stokes equations numerical simulation and two dimensional wind tunnel testing, the drag measuring technique for high lift configuration in low speed wind tunnel is researched. Navier-Stokes equations is solved for the flow around a multi-element airfoil, the wake flow characteristics behind the multi-element airfoil and the assumptions for conventional drag measuring method are analyzed, then a new more precise drag formula for two dimensional wind tunnel test is put forward; Based on the simulation results of multi-element airfoil flow, it’s aerodynamic performance is obtained respectively by integrating the surface pressure and friction drag, and computing with the information of wake flow according to conventional and newly proposed drag calculation formulas, and the three results are compared to verify the accuracy of the new drag formula; The wind tunnel test is carried out to ascertain the accuracy of the new drag formula. It is shown from the results that in the high-lift case the conventional drag formula with the wake information is of many limitations and must be improved, and the new drag formula presented in this paper is more accurate because of consideration of the wake flow characteristics of airfoil or two-dimensional configuration.

scholarly journals Reynolds number and wind tunnel wall effects on the flow field around a generic UHBR engine high-lift configuration

2020 ◽  
Vol 11 (4) ◽  
pp. 1009-1023 ◽  
Author(s):  
Junaid Ullah ◽  
Aleš Prachař ◽  
Miroslav Šmíd ◽  
Avraham Seifert ◽  
Vitaly Soudakov ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
Test Section ◽  
Large Scale ◽  
Scale Model ◽  
Small Scale ◽  
Wall Effects ◽  
Tunnel Wall ◽  
High Lift

Abstract RANS simulations of a generic ultra-high bypass ratio engine high-lift configuration were conducted in three different environments. The purpose of this study is to assess small scale tests in an atmospheric closed test section wind tunnel regarding transferability to large scale tests in an open-jet wind tunnel. Special emphasis was placed on the flow field in the separation prone region downstream from the extended slat cut-out. Validation with wind tunnel test data shows an adequate agreement with CFD results. The cross-comparison of the three sets of simulations allowed to identify the effects of the Reynolds number and the wind tunnel walls on the flow field separately. The simulations reveal significant blockage effects and corner flow separation induced by the test section walls. By comparison, the Reynolds number effects are negligible. A decrease of the incidence angle for the small scale model allows to successfully reproduce the flow field of the large scale model despite severe wind tunnel wall effects.

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