Difference between revisions of "CFD Simulations AC1-02"

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[http://qnet-ercoftac.cfms.org.uk/data/AC1/02/ac102c14cp07.dat ac102c14cp07.dat] (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, C<sub>P</sub>)
 
[http://qnet-ercoftac.cfms.org.uk/data/AC1/02/ac102c14cp07.dat ac102c14cp07.dat] (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, C<sub>P</sub>)
  
[http://qnet-ercoftac.cfms.org.uk/data/AC1/02/Cac102c14cp08.dat ac102c14cp08.dat] (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, C<sub>P</sub>)
+
[http://qnet-ercoftac.cfms.org.uk/data/AC1/02/ac102c14cp08.dat ac102c14cp08.dat] (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, C<sub>P</sub>)
  
 
[http://qnet-ercoftac.cfms.org.uk/data/AC1/02/ac102c14cp095.dat ac102c14cp095.dat] (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, C<sub>P</sub>)
 
[http://qnet-ercoftac.cfms.org.uk/data/AC1/02/ac102c14cp095.dat ac102c14cp095.dat] (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, C<sub>P</sub>)

Revision as of 12:13, 17 February 2010

Front Page

Description

Test Data

CFD Simulations

Evaluation

Best Practice Advice

RAE M2155 Wing

Application Challenge 1-02 © copyright ERCOFTAC 2004


Overview of CFD Simulations

Numerical simulation of the flow around the wing RAE M2155 have been performed at QINETIQ, for case 1-2-3-4, and at CIRA, only for case 2, with the main aim of validation and assessment of the turbulence models employed.

QINETIQ [3] has used the following turbulence models :

1) A k-ω based variant of the Menter SST scheme

2) A k-ω based EARSM utilising a novel calibration and incorporating explicitly the variable ratio of turbulence production to dissipation rate.

3) A tensorially linear version of the k-ω based EARSM model (only case 3).

while CIRA [4,5,6] has employed the

1) Spalart Allmaras

2) Myong-Kasagi κ-ε

3) Non Linear κ-ε (Myong-Kasagi κ-ε + 2nd order constitutive relation by Shih)

4) Standard Wilcox κ-ω

5) Kok TNT κ-ω

6) Menter SST κ-ω

turbulence models.

The aerodynamic coefficients, pressure and friction coefficients, and velocity profiles at several locations are available.


Table CFD-A Summary Description of All Test Cases
NAME GNDPs PDPs SPs
Re Mach Incidence (deg) Detailed Data DOAPs
CFD 11 4.1x106 0.744 2.5 CP CN
CFD 12 4.1x106 0.806 2.5 CP CN
CFD 13 4.1x106 0.846 1.5 CP CN
CFD 14 4.1x106 0.854 1.5 CP CN
CFD 22 4.1x106 0.806 2.5 CP, Cf, U CL,CD




Table CFD-B Summary Description of All Available Data Files and Simulated Parameters
SP1

CP

SP2

Cf

SP3

U

DOAPs, or other

miscellaneous data

CFD 12 ac102c12cp02.dat ac102c12cf02.dat ac102c12bla.dat ac102c12doap.dat
ac102c12cp03.dat ac102c12cf03.dat ac102c12blb.dat
ac102c12cp04.dat ac102c12cf04.dat ac102c12blc.dat
ac102c12cp05.dat ac102c12cf05.dat ac102c12bld.dat
ac102c12cp06.dat ac102c12cf06.dat
ac102c12cp07.dat ac102c12cf07.dat
ac102c12cp08.dat ac102c12cf08.dat
ac102c12cp095.dat ac102c12cf095.dat
CFD 14 ac102c14cp02.dat ac102c14cf02.dat ac102c14bla.dat ac102c14doap.dat
ac102c14cp03.dat ac102c14cf03.dat ac102c14blb.dat
ac102c14cp04.dat ac102c14cf04.dat ac102c14blc.dat
ac102c14cp05.dat ac102c14cf05.dat ac102c14bld.dat
ac102c14cp06.dat ac102c14cf06.dat
ac102c14cp07.dat ac102c14cf07.dat
ac102c14cp08.dat ac102c14cf08.dat
ac102c14cp095.dat ac102c14cf095.dat
CFD 22 ac102c22cp02.dat ac102c22cf02.dat ac102c22bla1.dat ac102c22doap.dat
ac102c22cp03.dat ac102c22cf03.dat ac102c22bla2.dat
ac102c22cp04.dat ac102c22cf04.dat ac102c22bla3.dat
ac102c22cp05.dat ac102c22cf05.dat ac102c22bla4.dat
ac102c22cp06.dat ac102c22cf06.dat ac102c22bla5.dat
ac102c22cp07.dat ac102c22cf07.dat ac102c22bla6.dat
ac102c22cp08.dat ac102c22cf08.dat ac102c22blb1.dat
ac102c22cp095.dat ac102c22blb2.dat
ac102c22blb3.dat
ac102c22blb4.dat
ac102c22blb5.dat
ac102c22blb6.dat
ac102c22bld1.dat
ac102c22bld2.dat
ac102c22bld3.dat
ac102c22bld4.dat
ac102c22bld5.dat
ac102c22bld6.dat

Simulation Case CFD-1

Solution strategy

The code used by QINETIQ for the computations is the BAE SYSTEMS RANSMB. This is a cell centered finite volume code with a central, Jameson type, flux approximation. A multigrid with a four stage Runge-Kutta scheme is used for time stepping.

The turbulence models used in the numerical simulations are :

1) A κ-g based variant of the Menter SST scheme

2) A κ-g based EARSM utilizing a novel calibration and incorporating explicitly the variable ratio of turbulence production to dissipation rate.

3) A tensorially linear version of the κ-g based EARSM model (only case 3).


Computational Domain

The computational domain includes the tunnel walls, and the computations have been performed as internal flow calculations.

The meshes used in the computations were generated at Aircraft Research Association and have approximately 1 million cells. That used by CIRA can be downloaded from ftp://www.cfse.ch/pub/cfse/read/m2155grid.tar.gz

The meshes are of constant cross section. The outflow plane is located at x=12m and the inflow plane is located at x=-12m for case 1 and 2, and at x=-2.5m for case 3 and 4. The wing leading edge at the root section is located at x=0. Therefore the entrance section of the mesh in much longer for case 1 and 2. This is due to problems encountered at ARA during the early computations.

The excessive length of the case 1 and 2 has been partly responsible for some case 2 poor results. The mesh has been recently modified at QINETIQ, so that the length of the entrance section of case 1 and 2 is the same as case 3 and 4.

Boundary Conditions

The following boundary conditions have been used :

• Inflow : Velocity and density prescribed, and pressure extrapolated from interior

• Outflow : Pressure prescribed, and velocity and density extrapolated from interior

• Tunnel walls where the wing is mounted on : No slip

• Tunnel walls not connected to the wing : Slip

• Wing surfaces : No slip


Application of Physical Models

All the turbulence models used in the computations employ a low Reynolds number formulation. The SST Menter requires the use of a blending function in order to switch from a κ-g to a κ-ε formulation.

The value of y+ at the first grid point is assumed to be O(1) and the mesh is thought to be fine enough to resolve the boundary layer.

Numerical Accuracy

• Grid refinement

q Studies were originally conducted at ARA by using a κ-ω model.

q Studies have not performed at QINETIQ due to the high cpu time requirements.

• Convergence

q The solutions show a three to four orders of magnitude reduction of the average density residuals. The typical magnitude of the average density residual at convergence is 10-5

CFD Results

The data consist of :

• Pressure Coefficients at y/b=0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.95

• Friction Coefficients at y/b= 0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.95

• Boundary layer results at points A,B,C and D

• Lift and drag (pressure and friction) coefficients


CFD12

ac102c12cp02.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp03.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp04.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp05.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp06.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp07.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp08.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cp095.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c12cf02.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf03.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf04.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf05.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf06.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf07.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf08.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12cf095.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c12bla.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c12blb.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c12blc.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c12bld.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c12doap.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns:CL, CD( pressure), CD(friction))

CFD14

ac102c14cp02.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp03.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp04.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp05.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp06.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp07.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp08.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cp095.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c14cf02.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf03.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf04.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf05.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf06.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf07.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf08.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14cf095.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c14bla.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c14blb.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c14blc.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c14bld.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: Z/C, U/UP, P/H)

ac102c14doap.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns:CL, CD( pressure), CD(friction))

References

[3] D.A. Peshkin. Technical Report: DERA/MSS/MSFC1/TR000228. Strictly limited circulation.


Simulation Case CFD-2

Solution strategy

CIRA has used the RANS flow solver ZEN version 6.0

The RANS equations are discretized by means of a cell centered finite volume scheme with blended self adaptive second and fourth order artificial dissipation. The solution procedure is based on a time marching concept. The multigrid scheme is used to accelerate the convergence of the solution, and performs relaxations, by using the Runge Kutta algorithm with local time stepping and residual averaging, on different grid levels. The turbulence equations are uncoupled by the RANS equations and are solved, inside a multigrid cycle, only on the finest grid level.

The turbulence models employed in the numerical simulations are the following :

1) Spalart Allmaras

2) Myong-Kasagi κ-ε

3) Non Linear κ-ε (Myong-Kasagi κ-ε + 2nd order constitutive relation by Shih)

4) Standard Wilcox κ-ω

5) Kok TNT κ-ω

6) Menter SST κ-ω

Computational Domain

The computational domain includes the wind tunnel walls, and the simulations have been performed as internal flow calculations. Therefore wall tunnel corrections are not necessary.

The inflow plane is located at x=-4m and the outflow plane at x=4.5m. The wing leading edge at the root section is located at x=0.

The mesh used has 36 blocks with 1.2 million point and can be run on 3 different levels.


Boundary Conditions

The following boundary conditions have been used :

1) Inflow : General free-stream with specified enthalpy and momentum, and the pressure extrapolated

2) Outflow : General free-stream with specified pressure and extrapolated velocity and enthalpy

3) Tunnel walls : Slip

4) Wing surfaces : Adiabatic no slip with fixed transition

The tunnel walls boundary layer has shown to have an effect up to 30% wing span.

%,


At the inflow the turbulent variables are assumed to be constant, and the free stream values are derived by :

Application of Physical Models

The Wilcox and TNT κ-ω turbulence models do not have a low Reynolds formulation, while the Spalart Allmaras and the κ-ε models employ the use of wall damping functions. The SST Menter κ-ω model, in order to switch from a κ-ω to a κ-ε formulation close to a solid boundary and to take into account the effect of the transport of the principal shear stress (SST formulation), requires the computation of blending functions.

The values of y+ at the first cell center is O(1)


Numerical Accuracy

The computations have been performed on 3 different grid levels.

For the κ-ω SST Menter turbulence model, for example, the following accuracy has been obtained :

• Grid sensitivity

q The lift coefficient changes less than 1% going from the 1st to the 2nd grid level, and less than 0.5% from the 2nd to the finest level.

q The drag coefficient changes of about 15% going from the 1st to the 2nd grid level, and less than 5% from the 2nd to the finest level.

• Convergence on the finest level

q In the last 500 iterations, the lift coefficient changes less than 0.02% and drag coefficient less than 0.03%.


CFD Results

The data consist of :

• Pressure coefficients at y/b=0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.95

• Friction coefficients at y/b= 0.2,0.3,0.4,0.5,0.6,0.7,0.8

• Velocity profiles at the stations A,B, and D

• Lift and drag (pressure and friction) coefficients

CFD22

ac102c22cp02.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp03.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp04.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp05.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp06.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp07.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp08.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cp095.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, CP)

ac102c22cf02.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22cf03.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22cf04.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22cf05.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22cf06.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22cf07.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22cf08.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns: x/c, Cf)

ac102c22bla1.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bla2.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bla3.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bla4.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bla5.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bla6.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22blb1.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22blb2.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22blb3.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22blb4.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22blb5.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22blb6.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bld1.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bld2.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bld3.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bld4.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bld5.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22bld6.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence, turbulence model; columns: Z/C, U/UP)

ac102c22doap.dat (ASCII file; headers: Mach number, Reynolds number, angle of incidence; columns:Turbulence model, CL, CD( pressure), CD(friction))

References

[4] M. Amato, P. Catalano, “An Evaluation of Stress-Strain Relationships for Aeronautical Applications”, XV AIDAA National Congress

[5] M. Amato, P.Catalano, “Non Linear κ-ε Turbulence Modeling for Industrial Applications”, ICAS 2000 Conference

[6] P. Catalano, M. Amato, “Assessment of κ-ω Turbulence modeling in the CIRA Flow Solver ZEN”, ECCOMAS CFD 2001 Conference

© copyright ERCOFTAC 2004



Contributors: Pietro Catalano - CIRA; QinetiQ

Site Design and Implementation: Atkins and UniS


Front Page

Description

Test Data

CFD Simulations

Evaluation

Best Practice Advice