Study of Reynolds number effects on the aerodynamics of a moderately thick airfoil using a high-pressure wind tunnel

2021 ◽  
Vol 62 (8) ◽  
Author(s):  
Claudia E. Brunner ◽  
Janik Kiefer ◽  
Martin O. L. Hansen ◽  
Marcus Hultmark
Keyword(s):  
Reynolds Number ◽  
High Pressure ◽  
Wind Tunnel ◽  
Thick Airfoil ◽  
Reynolds Number Effects

scholarly journals Estimation of Aerodynamic Coefficients in a Small Subsonic Wind Tunnel

2018 ◽  
Vol 30 (4) ◽  
pp. 457-463
Author(s):  
Karolina Krajček Nikolić ◽  
Anita Domitrović ◽  
Slobodan Janković
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Internal Force ◽  
Force Balance ◽  
Wind Tunnels ◽  
Subsonic Wind Tunnel ◽  
Lower Reynolds Number ◽  
Scaling Methods ◽  
Reynolds Number Effects ◽  
Wind Tunnel Data

To apply the experimental data measured in a wind tunnel for a scaled aircraft to a free-flying model, conditions of dynamical similarity must be met or scaling procedures introduced. The scaling methods should correct the wind tunnel data regarding model support, wall interference, and lower Reynolds number. To include the necessary corrections, the current scaling techniques use computational fluid dynamics (CFD) in combination with measurements in cryogenic wind tunnels. There are a few methods that enable preliminary calculations of typical corrections considering specific measurement conditions and volume limitation of test section. The purpose of this paper is to present one possible approach to estimating corrections due to sting interference and difference in Reynolds number between the real airplane in cruise regime and its 1:100 model in the small wind tunnel AT-1. The analysis gives results for correction of axial and normal force coefficients. The results of this analysis indicate that the Reynolds number effects and the problem of installation of internal force balance are quite large. Therefore, the wind tunnel AT-1 has limited  usage for aerodynamic coefficient determination of transport airplanes, like Dash 8 Q400 analyzed in this paper.

The Use of Air-Measured Profile Data for Application in a High Pressure Steam Turbine

2017 ◽  
Author(s):  
Marcus Britz ◽  
Peter Jeschke ◽  
Oliver Brunn ◽  
Thomas Polklas
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
High Pressure ◽  
Wind Tunnel ◽  
Steam Turbine ◽  
Blade Profile ◽  
Profile Data ◽  
High Pressure Steam ◽  
Pressure Steam ◽  
Measured Profile

This paper investigates the validity of the current industrial procedure of measuring optimized blade profiles in a wind tunnel under air condition although they are applied in a steam turbine. Therefore, it is important to analyze the possibility of using air-measured profile data for optimizing steam turbine blades. To this end, experimental data is collected using the cylindrical datum blade of a steam turbine in a three-stage high pressure steam turbine and in an annular air cascade wind tunnel. Three-dimensional CFD simulations are separately performed for both setups and show a good agreement with the experimental data. The numerical simulations can therefore be assumed to represent the real flow conditions. Firstly, for analyzing aerodynamic transferability, two optimized profiles are measured in the annular air cascade wind tunnel at Reynolds number of 6 × 105. These profile sections are designed for high and intermediate pressure applications by employing an optimizer. The optimization is performed with the focus on reducing the profile loss for steam conditions. The experimental data verifies that the losses of the optimized profiles are reduced significantly compared to the datum blade profile measured in the same air rig. Secondly, the air-measured optimized blade profiles are used to design a 3D-optimized blade. In a numerical investigation, this optimized blade is analyzed in the steam turbine by applying steam conditions. The outlet Reynolds number of the 2nd stage is 8 × 105. This configuration is compared with the numerical results of the datum blade profile simulations. The relative isentropic total-to-total efficiency is increased by 0.6% due to the use of the optimized rotor blades. The benefit persists also for a maximum outlet Reynolds number of 9 × 106.

The influence of Reynolds and Mach numbers on two-dimensional wind-tunnel testing: An experience

2011 ◽  
Vol 115 (1166) ◽  
pp. 249-254 ◽  
Author(s):  
B. Rasuo
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Side Wall ◽  
Boundary Layer Control ◽  
Two Dimensional ◽  
Number Range ◽  
Wall Boundary Layer ◽  
Reynolds Number Effects ◽  
Naca 0012 ◽  
Layer Control

Abstract In this note, the experimental results of wind-tunnel measurements of lift coefficient and lift-curve slope for aerofoil NACA 0012 obtained from the VTI-Institute Zarkovo, are presented. The results were obtained from tests and integrations of surface static-pressure data over a model of the NACA 0012 aerofoil section. The data were obtained for a free-stream Mach number range of 0·25-0·8 and a chord Reynolds number range of 2-25MRe. The essential results of these measurements along with the results from other authors are presented and evaluated. The principal factors which influence the accuracy of two-dimensional wind-tunnel test results are analysed. The influences of Reynolds number, Mach number and wall interference with reference to solid and flow blockage as well as the influence of side-wall boundary-layer control are analysed. Interesting results brought to light the Reynolds number effects of the test model versus Reynolds number effects of the facility in subsonic and transonic flow as well as the effects of the side-wall boundary-layer control and wall interference.

Microphone array wind tunnel measurements of Reynolds number effects in high-speed train aeroacoustics

Noise Notes ◽  
2012 ◽  
Vol 11 (4) ◽  
pp. 35-62
Author(s):  
Andreas Lauterbach ◽  
Klaus Ehrenfried ◽  
Sigfried Loose ◽  
Claus Wagner
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
High Speed ◽  
Microphone Array ◽  
High Speed Train ◽  
Wind Tunnel Measurements ◽  
Reynolds Number Effects
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