UFR 2-11 Test Case: Difference between revisions

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== Test Case Experiments ==
== Test Case Experiments ==
A detailed description of the test facility and measurement  techniques
A detailed description of the test facility and measurement  techniques
used in the experiments is given in [27, 28]. So here we  present  only
used in the experiments is given in
[‌[[UFR_2-11_References#27|27]], 28].
So here we  present  only
concise information about these aspects of the test case.
concise information about these aspects of the test case.


As already mentioned, the width of  the  experimental  section  is  7.2
As already mentioned, the width of  the  experimental  section  is  7.2
airfoil chord lengths c and its height is 16c.The two-dimensionality of
airfoil chord lengths ''c'' and its height is 16''c''.The two-dimensionality of
the flow over the NACA0021  model  was  improved  by  the  use  of  the
the flow over the NACA0021  model  was  improved  by  the  use  of  the
endplates (see Figure 2). It was found that the free-stream flow has  a
endplates (see Figure 2). It was found that the free-stream flow has  a

Revision as of 13:56, 6 September 2011

High Reynolds Number Flow around Airfoil in Deep Stall

Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References

Flows Around Bodies

Underlying Flow Regime 2-11

Test Case Study

Brief Description of the Test Case

The following presents a precise description of the primary test case, the NACA0021 airfoil at 60° angle of attack.


A visual impression of the geometry and flow has been shown in Figure 1. The experiments were carried out in the wind tunnel of Monash University (see Figure 2). The width of the experimental section is 7.2 airfoil chord lengths, c, and its height is 16c.


UFR2-11 figure2a.jpg|UFR2-11 figure2b.gif
Figure 2: NACA0021 airfoil in wind tunnel (left) and a plan view of wind tunnel (right) [ ]


The airfoil geometry normalized with the chord length, c, is defined by:



Experimental flow parameters, needed to set up appropriate numerical simulations, are presented in Table 2.


Table 2: Flow parameters
Parameter Notation Value
Reynolds number 2.7×105
Chord length 0.125 m
Angle of attack 60°
Free stream Mach number 0.1
Free stream streamwise turbulence intensity 0.6%


The flow parameters measured in the experiments are as follows:

  • Time-averaged pressure coefficient distribution over the airfoil surface, , where is the reference pressure from the undisturbed far-field flow and is the fluid density.


  • Time-averaged sectional drag and lift coefficients, integrated from pressure at individual spanwise locations near the spanwise mid-point: , where and are the sectional pressure drag and lift forces, respectively.


  • Time histories of the sectional lift and drag coefficients (32,000 points total over the time interval T≈9000 (c/U0)).


These data are available on the web site of the DESider EU project [‌5] in digital form: http://cfd.mace.manchester.ac.uk/desider/

Test Case Experiments

A detailed description of the test facility and measurement techniques used in the experiments is given in [‌27, 28]. So here we present only concise information about these aspects of the test case.

As already mentioned, the width of the experimental section is 7.2 airfoil chord lengths c and its height is 16c.The two-dimensionality of the flow over the NACA0021 model was improved by the use of the endplates (see Figure 2). It was found that the free-stream flow has a turbulence intensity of 0.6% and variations of the velocity over the central 0.3m×0.3m area of the test section are less than 3%. During the runs the dynamic pressure was determined by a Pitot upstream of and above the model. This allowed the coefficient of pressure to be determined for each sample. Although the flow decelerates over the distance from the Pitot to the section containing the model, an error in velocity caused by this was less than 6% and was not corrected for.

CFD Methods




Contributed by: Charles Mockett; Misha Strelets — CFD Software GmbH and Technische Universitaet Berlin; New Technologies and Services LLC (NTS) and Saint-Petersburg State University

Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References


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