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Exp: CFDVAL2004 Case 3 Details and Submission Guidelines

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Relevant details for Case 3 are as follows:

M_freestream = 0.10

The atmospheric conditions varied, but were essentially standard atmospheric conditions at sea level in a wind tunnel vented to the atmosphere, in a temperature-controlled room. These conditions can be given as approximately:

p_ambient = approx 101325 kg/(m-s^2)

T_ambient = approx 298 K

Some derived relevant conditions are:

density_ambient = approx 1.185 kg/m^3

viscosity_ambient = approx 18.4e-6 kg/(m-s)

u_freestream = approx 34.6 m/s

Re_freestream = approx 2.23e6 per meter, or approx 9.36e5 per chord length of hump

The upstream boundary conditions from the experiment (associated with the boundary layer on the plate at location x/c=-2.14 upstream of the start of the hump, where c = 16.536 inches = 0.4200 m), to be used to help set/verify CFD inflow BCs, are given in the following files:

u-velocity BCs from experiment (pitot probe), updated 29 October 2003
u' streamwise turbulent intensity BCs from experiment (hot wire)
To complete the Reynolds stress matrix for the upstream BCs at x/c=-2.14, assume incompressible fully-developed boundary layer distributions

There are two required conditions for case 3: (1) no suction case and (2) suction case. A third oscillatory control case is also defined; however, there is no experimental data available for it as of the March 2004 workshop date, so the condition is optional.

Condition 1: no flow control (no flow through the 23-inch-span slot; slot left open with no suction or blowing through it)
Condition 2: suction rate of 0.01518 kg/s (27.13 CFM) through the 23-inch-span slot (updated 5 September 2003)
Condition 3 (optional): zero-net-mass-flux oscillatory suction/blowing, frequency = 138.5 Hz, peak velocity out of slot (Ujetmax) during blowing part of cycle = 26.6 m/s (This condition corresponds to an oscillatory blowing momentum coefficient of approximately <cmu> = <J>/(cq) = rho*h*(Ujetrms)²/(c*0.5*rhoinf*Uinf²) = 0.111%, where h is the slot width). Note: the oscillatory suction/blowing case used a different unit underneath the splitter plate, feeding into the slot. As a result, the blockage beneath the splitter plate was different, which slightly affected the incoming flow field above the plate. Thus, the boundary layer thickness at x/c=-2.14 for the oscillatory case was slightly smaller than for the no-flow and steady suction cases. The corresponding data with these upstream BCs are in the following files (not available in time for the March 2004 workshop): u-velocity BCs, u'-turbulence BCs, posted 12 August 2004

Submission Guidelines:

(Last updated for the March 2004 workshop: 18 November 2003)
(Additional update for optional condition 3 posted: 20 January 2005)

Submissions for this case should include both conditions of no-flow-control and steady-suction. The third condition of oscillatory blowing control is optional. The purpose here is to determine the state-of-the-art in modeling these types of flows, so we want to explore which CFD methods work and which do not.

You can either model the internal cavity or specify a boundary condition at the slot exit.
You may choose to model the flowfield two-dimensionally or three-dimensionally (if three-dimensionally, you may choose to model the endplates or you may employ periodic or some other appropriate spanwise boundary condition).

There is the requirement that you detail specifically how you choose to model the case, including all boundary conditions and approximations made. As we assess the methodologies used at the workshop, it will be important to know as many details as possible about the calculations/simulations.

Detailed requirements include:

1. The no-flow-control and steady-suction conditions may be run either time-accurately or in steady-state mode, depending on your computational method. The optional oscillatory blowing control condition (if computed) must be run time-accurately, in order to simulate the unsteady nature of the case.

1a. RANS codes run in time-accurate mode (e.g., URANS) solve directly for phase-averaged variables, i.e. <u_i> and <u'_iu'_j>. Click on link to PDF write-up for more details. Therefore, time-accurate RANS simulations should result in repeating or very-nearly-repeating periodic solutions. When periodicity is achieved, averages over one or more periods of oscillation yields the long-time-averaged (time-independent mean) values for these quantities.
1b. DNS, LES, or DES simulations will need to be post-processed to obtain the long-time-averaged (time-independent mean) values.

2. GRID STUDY: If you choose to model this case two-dimensionally, then it is strongly suggested that you perform the computation using at least two different grid sizes in order to assess the effect of spatial discretization error on the solution. If you model it three-dimensionally, then solutions using more than one grid size are encouraged, but not required. If you use more than one grid, submit each set of results separately.

3. TIME STEP STUDY (for time-accurate computations only): If you choose to model this case two-dimensionally, then it is strongly suggested that you perform the computation using at least two different time step sizes in order to assess the effect of temporal discretization error on the solution. If you model it three-dimensionally, then solutions using more than one time step are encouraged, but not required. If you use more than one time step, submit each set of results separately.

Specific quantities that result from your computations at particular locations will be required for submission. Note that for all the following, we adopt the coordinate system with x downstream and y up, with the (x,y)=(0,0) origin at the start of the hump. All results from 3-D computations are to be given at the z=0 location (centerplane of the tunnel). The chord "c" is the length of the bump: 16.536 inches. The requirements follow (if you are unable to provide a particular quantity, simply leave it out of the "variable" list, and reduce the number of columns of data submitted):

a. x/c vs. Cp on the lower wall for no-flow and
suction cases.  For time-accurate computations,
this should be the long-time-averaged Cp.  The definition for Cp
is Cp=(p-pinf)/(0.5*rhoinf*uinf^2), where the "inf" values should
correspond to the upstream "freestream" location where M=0.1.
Submit these results for both conditions of
no-flow-through-the-slot, and for that of constant suction.
Include results at least as far upstream as x/c=-2.14, and
at least as far downstream as x/c=2.0.
Do not include the data on the walls deep inside the slot.
   Name this file: case3.cp.ANYTHING.dat
    -where "ANYTHING" can be any descriptor you choose (should
     be different for each file if you are submitting multiple
     runs)
    -the file should be in 2-column format:
      1st line: #your name (pound sign needed)
      2nd line: #your affiliation (pound sign needed)
      3rd line: #your contact info (pound sign needed)
      4th line: #brief description of grid (pound sign needed)
      5th line: #brief description of code/method (pound sign needed)
      6th line: #other info about the case, such as spatial accuracy (pound sign needed)
      7th line: #other info about the case, such as turb model (pound sign needed)
      8th line: #other info about the case (pound sign needed)
      9th line: variables="x/c","Cp"
     10th line: zone t="surface Cp, no flow case"
     subsequent lines:  x/c  Cp  <- this is the data for no flow case
     next line: zone t="surface Cp, suction case"
     subsequent lines:  x/c  Cp  <- this is the data for suction case

Download sample file case3.cp.SAMPLE.dat

b. x/c vs. Cf on the lower wall for no-flow and
suction cases.  For time-accurate computations,
this should be the long-time-averaged Cf.  The definition for Cf
is Cf=tauw/(0.5*rhoinf*uinf^2), , where the "inf" values should
correspond to the upstream "freestream" location where M=0.1.
The term tauw stands for mu*(du/dy) at the wall.
Give these results for both conditions of
no-flow-through-the-slot, and that of constant suction.
Include results at least as far upstream as x/c=-2.14, and
at least as far downstream as x/c=2.0.
Do not include the data on the walls deep inside the slot.
   Name this file: case3.cf.ANYTHING.dat
    -where "ANYTHING" can be any descriptor you choose (should
     be different for each file if you are submitting multiple
     runs)
    -the file should be in 2-column format:
      1st line: #your name (pound sign needed)
      2nd line: #your affiliation (pound sign needed)
      3rd line: #your contact info (pound sign needed)
      4th line: #brief description of grid (pound sign needed)
      5th line: #brief description of code/method (pound sign needed)
      6th line: #other info about the case, such as spatial accuracy (pound sign needed)
      7th line: #other info about the case, such as turb model (pound sign needed)
      8th line: #other info about the case (pound sign needed)
      9th line: variables="x/c","Cf"
     10th line: zone t="surface Cf, no flow case"
     subsequent lines:  x/c  Cf  <- this is the data for no flow case
     next line: zone t="surface Cf, suction case"
     subsequent lines:  x/c  Cf  <- this is the data for suction case

Download sample file case3.cf.SAMPLE.dat

c. Velocity profiles and turbulence data at several stations along 
the lower wall for no-flow and suction cases.
For time-accurate computations, these should be the long-time-averaged
profiles.  The 15 required stations are:  x/c=-2.14,
0,.2,.4,.65,.66,.8,.9,1.0,1.1,1.2,1.3,1.4,1.6,2.0.  The profiles
should be taken along a VERTICAL line at each given x-location
(not necessarily normal to the hump surface), extending from the
wall up to at least past the boundary layer and/or separation bubble.  
Also, if your computations included the inside of the slot, include
profiles along one line at x/c=0.647 inside the slot (from the lower
wall to the upper wall, y/c goes from approximately 0.1105 to 0.1142
at this x location).  Submit the following quantities:
u/Uinf, v/Uinf, u'u'bar/Uinf^2, v'v'bar/Uinf^2, and u'v'bar/Uinf^2, where:
   u = horizontal velocity component
   v = vertical velocity component
   u'u'bar = turbulent normal stress in horizontal direction (optional)
   v'v'bar = turbulent normal stress in vertical direction (optional)
   u'v'bar = turbulent shear stress in x-y plane
Submit two separate files, one for no-flow-control, and one for
constant suction.
   Name these files: case3.pro.noflow.ANYTHING.dat
                     case3.pro.suction.ANYTHING.dat
    -where "ANYTHING" can be any descriptor you choose (should
     be different for each file if you are submitting multiple
     runs)
    -the file should be in 7-column format:
      1st line: #your name (pound sign needed)
      2nd line: #your affiliation (pound sign needed)
      3rd line: #your contact info (pound sign needed)
      4th line: #brief description of grid (pound sign needed)
      5th line: #brief description of code/method (pound sign needed)
      6th line: #other info about the case, such as spatial accuracy (pound sign needed)
      7th line: #other info about the case, such as turb model (pound sign needed)
      8th line: #other info about the case (pound sign needed)
      9th line: variables="x/c","y/c","u/Uinf","v/Uinf","uu/Uinf^2",
        "vv/Uinf^2","uv/Uinf^2"
     10th line: zone t="x/c=-2.14"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=-2.14
     next line: zone t="x/c=0"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0
     next line: zone t="x/c=0.2"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.2
     next line: zone t="x/c=0.4"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.4
     next line: zone t="x/c=0.65"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.65
     next line: zone t="x/c=0.66"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.66
     next line: zone t="x/c=0.8"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.8
     next line: zone t="x/c=0.9"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.9
     next line: zone t="x/c=1.0"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.0
     next line: zone t="x/c=1.1"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.1
     next line: zone t="x/c=1.2"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.2
     next line: zone t="x/c=1.3"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.3
     next line: zone t="x/c=1.4"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.4
     next line: zone t="x/c=1.6"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.6
     next line: zone t="x/c=2.0"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=2.0
     next line: zone t="inside slot, x/c=0.647"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data inside slot at x/c=0.647

Download sample file case3.pro.noflow.SAMPLE.dat

d.  Field line-contour-plots (in one of the following formats: ps, eps, or jpg)
of streamlines (average streamlines for time-accurate computations) 
for no-flow and suction cases.  These
plots should be black-and-white line plots only.
The plots should go from approximately x/c=0.6 to 1.6, and should contain
enough streamlines to show the approximate size and shape of the
separation bubble.  The x-to-y ratio of the plot should be 1.0.
The purpose of submitting these plots is to get
a qualitative picture of the flowfields.  Altogether, submit 2 plots files,
one for the no-flow-control case and one for the steady suction case.
   Name these files: case3.stream.noflow.ANYTHING.eps
                     case3.stream.suction.ANYTHING.eps
(where the "eps" in this case means encapsulated postscript - use ps,
or jpg instead if appropriate).

e. (For optional condition 3 only) x/c vs. long-time-averaged Cp 
on the lower wall for oscillatory case.
Include results at least as far upstream as x/c=-2.14, and
at least as far downstream as x/c=2.0.
Do not include the data on the walls deep inside the slot.
   Name this file: case3.cposc.ANYTHING.dat
    -where "ANYTHING" can be any descriptor you choose (should
     be different for each file if you are submitting multiple
     runs)
    -the file should be in 2-column format:
      1st line: #your name (pound sign needed)
      2nd line: #your affiliation (pound sign needed)
      3rd line: #your contact info (pound sign needed)
      4th line: #brief description of grid (pound sign needed)
      5th line: #number of time steps per cycle (pound sign needed)
      6th line: #brief description of code/method (pound sign needed)
      7th line: #other info about the case, such as spatial accuracy (pound sign needed)
      8th line: #other info about the case, such as turb model (pound sign needed)
      9th line: #other info about the case (pound sign needed)
     10th line: variables="x/c","Cp"
     11th line: zone t="surface Cp, oscillatory case"
     subsequent lines:  x/c  Cp  <- this is the data for oscillatory case

Download sample file case3.cposc.SAMPLE.dat

f. (For optional condition 3 only - added after March 2004 Workshop) 
x/c vs. phase-averaged <Cp> on the lower 
wall for oscillatory case, at phases = 80 deg, 170 deg (peak blowing at slot),
260 deg, and 350 deg.
Include results at least as far upstream as x/c=0.6, and
at least as far downstream as x/c=1.8.
Do not include the data on the walls deep inside the slot.
   Name this file: case3.cposcphase.ANYTHING.dat
    -where "ANYTHING" can be any descriptor you choose (should
     be different for each file if you are submitting multiple
     runs)
    -the file should be in 2-column format:
      1st line: #your name (pound sign needed)
      2nd line: #your affiliation (pound sign needed)
      3rd line: #your contact info (pound sign needed)
      4th line: #brief description of grid (pound sign needed)
      5th line: #number of time steps per cycle (pound sign needed)
      6th line: #brief description of code/method (pound sign needed)
      7th line: #other info about the case, such as spatial accuracy (pound sign needed)
      8th line: #other info about the case, such as turb model (pound sign needed)
      9th line: #other info about the case (pound sign needed)
     10th line: variables="x/c","Cp"
     11th line: zone t="phase=80 deg surface Cp, oscillatory case"
     subsequent lines:  x/c  Cp  <- this is the phase=80 data for oscillatory case
     next line: zone t="phase=170 deg surface Cp, oscillatory case"
     subsequent lines:  x/c  Cp  <- this is the phase=170 data for oscillatory case
     next line: zone t="phase=260 deg surface Cp, oscillatory case"
     subsequent lines:  x/c  Cp  <- this is the phase=260 data for oscillatory case
     next line: zone t="phase=350 deg surface Cp, oscillatory case"
     subsequent lines:  x/c  Cp  <- this is the phase=350 data for oscillatory case

Download sample file case3.cposcphase.SAMPLE.dat

g. (For optional condition 3 only - added after March 2004 Workshop), updated 24 January 2005 
Phase-averaged velocity profiles and turbulence
data at 4 different phases during the cycle:  80 deg, 170 deg (peak blowing at slot), 
260 deg, and 350 deg.  Submit the following phase-averaged
<> quantities:  u/Uinf, v/Uinf, u'u'bar/Uinf^2, v'v'bar/Uinf^2,
and u'v'bar/Uinf^2, where:
   u = phase-averaged horizontal velocity component
   v = phase-averaged vertical velocity component
   u'u'bar = phase-averaged turbulent normal stress in horizontal direction (optional)
   v'v'bar = phase-averaged turbulent normal stress in vertical direction (optional)
   u'v'bar = phase-averaged turbulent shear stress in x-y plane
The 9 required stations are: x/c=0.65, 0.66, 0.67, 0.68, 0.8, 0.9, 1.0, 1.1, 1.2.
The profiles should be taken along a VERTICAL line at each given x-location
(not necessarily normal to the hump surface), extending from the
wall up to at least past the boundary layer and/or separation bubble.
Additionally, include profiles at a 10th station along one line right at the slot exit 
from approximately (x/c,y/c)=(0.65416,0.11501) to (0.65848,0.11358) (this line is 
aligned with the body surface over the slot).
   Name these files: case3.pro.oscphase080.ANYTHING.dat
                     case3.pro.oscphase170.ANYTHING.dat
                     case3.pro.oscphase260.ANYTHING.dat
                     case3.pro.oscphase350.ANYTHING.dat
    -where "ANYTHING" can be any descriptor you choose (should
     be different for each file if you are submitting multiple
     runs)
    -the file should be in 7-column format:
      1st line: #your name (pound sign needed)
      2nd line: #your affiliation (pound sign needed)
      3rd line: #your contact info (pound sign needed)
      4th line: #brief description of grid (pound sign needed)
      5th line: #number of time steps per cycle (pound sign needed)
      6th line: #brief description of code/method (pound sign needed)
      7th line: #other info about the case, such as spatial accuracy (pound sign needed)
      8th line: #other info about the case, such as turb model (pound sign needed)
      9th line: #other info about the case (pound sign needed)
     10th line: variables="x/c","y/c","u/Uinf","v/Uinf","uu/Uinf^2",
        "vv/Uinf^2","uv/Uinf^2"
     11th line: zone t="x/c=0.65"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.65
     next line: zone t="x/c=0.66"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.66
     next line: zone t="x/c=0.67"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.67
     next line: zone t="x/c=0.68"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.68
     next line: zone t="x/c=0.8"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.8
     next line: zone t="x/c=0.9"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=0.9
     next line: zone t="x/c=1.0"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.0
     next line: zone t="x/c=1.1"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.1
     next line: zone t="x/c=1.2"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data at x/c=1.2
     next line: zone t="slot exit, (x/c,y/c)=(0.65416,0.11501) to (0.65848,0.11358)"
     subsequent lines:  x/c  y/c  u/Uinf  v/Uinf
            uu/Uinf^2  vv/Uinf^2  uv/Uinf^2 <- this is the data along the slot exit

Download sample file case3.pro.oscphase080.SAMPLE.dat

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