Contents:
Authors: David A. Boger
Date: July, 2006
USURP plays the same role as MIXSUR and OVERINT in that it can be used to perform flow coefficient computation and analysis on overset grids. USURP uses polygon clipping to determine the amount of non-overlapping area in each quad and optionally triangulates the remaining portions of each quad for visualization or use by subsequent tools. USURP also serves the role of OVERINT as an integrator for computing force, moment and mass flow rate coefficients.
USURP can be run in batch mode on any machine that supports Fortran 90/95. More detailed descriptions on the usage and on examples are given in the long version of the user's manual, GuideToUSURP.pdf, which is included in the CGT doc folder.
Details of the algorithm can be found in
Boger, D. A. and Dreyer, J. J., Prediction of Hydrodynamic Forces and Moments for Underwater Vehicles Using Overset Grids, AIAA Paper 2006-1148, 44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, January 2006.
Comments, questions, bug reports can be sent to dab143@only.arl.psu.edu.
USURP is executed by typing
usurp [command line options] < [input parameters filename] > [output messages filename]
A list and short description of the command line options can be obtained by typing
usurp --help
The input files required are:
------------------------------------------------------------------------------------
Description File Type Filename
------------------------------------------------------------------------------------
Surface or volume grids * PLOT3D unformatted multiple grid file grid.in
Solution Q file *,** PLOT3D unformatted multiple grid file q.save
Input parameters (STDIN) *** ASCI
------------------------------------------------------------------------------------
* must supply at least 2 planes from all walls for viscous force computation
** the solution file is not needed if only panel weights for OVERFLOW are desired
*** the same input parameters file that is used to run both MIXSUR and OVERINT is also used to run USURP
USURP produces a number of output files that can be used for visualization or as input to other tools such as OVERFLOW and CART3D. Much of the output is equivalent to files generated by MIXSUR or OVERINT. If the solution file is provided, USURP writes the flow coefficients info to STDOUT. Visualization can be facilitated by using Tecplot. Output files include the following:
1. panel_weights.dat: The primary result from USURP consists of a weight between 0.0 and 1.0 for each quad in the original mesh. This file can be generated in a pre-processing step and provided to OVERFLOW to be included OVERFLOW's native force and moment integrator.
2. usurp-surfaces.plt: Hybrid grid for visualization in Tecplot.
3. grid.i.tri: A CART3D surface triangulation file that includes the entire surface domain, generated only when the --full-surface or --watertight command line options are used and the solution file is not present (or the --ignore-solution command line option is used). This triangulation consists of all the quads and triangles on the hybrid surface.
4. grid.i.triq: An annotated CART3D triangulation file that contains the grid plus 5 q dependent flow variables on the triangulated surface, generated only when the solution file is present and either the --full-surface or --watertight command line option is used.
A sample input parameters file and explanation of the input parameters are given below. The description is copied directly from the short version of the user's manual for FOMOCO.
0.8, 2.0, 0.0, 0.0, 1.4, 507.0 FSMACH,ALPHA,BETA,REY,GAMINF,TINF
3 NREF
1.0, 1.0, 0.0, 0.0, 0.0 REFL,REFA,XMC,YMC,ZMC
1.0, 1.0, 0.0, 0.0, 0.0, 2.0, 1.0 REFL,REFA,XMC,YMC,ZMC,REFLY,REFLZ
1.0, 1.0, 0.5, 0.2, 0.0, 0.5, 1.0, 0.1 REFL,REFA,XMC,YMC,ZMC,XMH,YMH,ZMH
1 NSURF
4, 1 NSUB, IREF
1, 3, 1, -1, 2, -2, 1, 1 NG,IBDIR,JS,JE,KS,KE,LS,LE
2, 3, 19, 219, 1, -1 1, 1 NG,IBDIR,JS,JE,KS,KE,LS,LE
3, 3, 1, -1, 1, 14 1, 1 NG,IBDIR,JS,JE,KS,KE,LS,LE
3, 3, 19, 219, 14, -1 1, 1 NG,IBDIR,JS,JE,KS,KE,LS,LE
1 NPRI
3, 1 NU1,NU2
0 NCOMP
FSMACH > 0 Free stream Mach number
<= 0 Read free stream Mach number from q.save
ALPHA in range [-360,360] Angle of attack
outside of [-360,360] Read angle of attack from q.save
BETA in range [-360,360] Side slip angle
outside of [-360,360] Read side slip angle from q.save
REY > 0 Reynolds number for viscous flow
= 0 Inviscid flow assumed
< 0 Read Reynolds number from q.save
GAMINF = Free stream ratio of specific heats
TINF = Free stream temperature (Rankine)
NREF = Number of reference conditions
Repeat the following for each reference condition
{
REFL > 0 Reference length for fomo coefficients
<= 0 Use 1.0 as default reference length
REFA > 0 Reference area for fomo coefficients
<= 0 Use total integrated surface area from defined
subsets as default reference area
XMC,YMC,ZMC = X,Y,Z coordinates of moment axes center
REFLY,REFLZ = reference lengths for Y and Z moments
[if 2 extra real optional inputs are found]
XMH,YMH,ZMH = X,Y,Z coordinates of hinge moment axis vector head
[if 3 extra real optional inputs are found] *
}
NSURF = Number of surfaces to compute coefficients
Repeat the following for each integration surface
{
NSUB = Number of subsets that belong to the surface
IREF = Reference conditions set for the surface
Repeat the following for each subset
[
NG = Grid number
IBDIR = Direction of surface normal
(1 = +J, -1 = -J, 2 = +K, -2 = -K, 3 = +L, -3 = -L)
JS,JE = Start and end indices in J
KS,KE = Start and end indices in K
LS,LE = Start and end indices in L
]
NPRI = Number of subset pairs to specify priority
For each subset pair, enter
[
NU1 > 0, NU2 > 0 : Subset numbers within surface where subset NU1 will
be kept if it overlaps subset NU2
or
NU1 < 0, NU2 < 0 : Subset numbers within surface between which no zipper
grids should be created, e.g., abutting subsets
]
}
NCOMP = Number of components
Repeat the following for each component
{
[ component name ]
NIS = Number of integration surfaces for the component
IREF = Reference conditions set for the component
[ List of surface numbers for surfaces, negative numbers will contribute
negative forces/moments to the total ]
}
* If optional input XMH,YMH,ZMH are present, the hinge moment axis vector
base is taken from XMC,YMC,ZMC.