[Moose21]

Hello guys,

I am trying to do a supersonic simulation using SU2. The simulation does generate a normal shock as expected however the flow goes to hypersonic speeds at the back of the model. Which I am not sure why. If anyone can explain it or show me how to fix it, I would really appreciate it. The SU2 version is 7.3.1
(My code and a screenshot is attached below)

Image link: https://ibb.co/nwZTM7K

Code:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% SU2 configuration file %
% Case description: Transonic inviscid flow around a NACA0012 Airfoil %
% Author: Moose21 %
% Institution: Virginia Tech %
% Date: 03/31/2022 %
% File Version 7.3.0 "Blackbird" %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% ------------- DIRECT, ADJOINT, AND LINEARIZED PROBLEM DEFINITION ------------%
%
% Physical governing equations (EULER, NAVIER_STOKES,
% WAVE_EQUATION, HEAT_EQUATION, FEM_ELASTICITY,
% POISSON_EQUATION)
SOLVER= EULER
%
% Mathematical problem (DIRECT, CONTINUOUS_ADJOINT)
MATH_PROBLEM= DIRECT
%
% Restart solution (NO, YES)
RESTART_SOL= NO

% ----------- COMPRESSIBLE AND INCOMPRESSIBLE FREE-STREAM DEFINITION ----------%
%
% Mach number (non-dimensional, based on the free-stream values)
MACH_NUMBER= 3.5
%
% Angle of attack (degrees)
AOA= 0
%
% Free-stream pressure (101325.0 N/m^2 by default, only Euler flows)
FREESTREAM_PRESSURE= 30150.774
%
% Free-stream temperature (273.15 K by default)
FREESTREAM_TEMPERATURE= 228.8

% -------------- COMPRESSIBLE AND INCOMPRESSIBLE FLUID CONSTANTS --------------%
% Different gas model (STANDARD_AIR, IDEAL_GAS, VW_GAS, PR_GAS)
FLUID_MODEL = IDEAL_GAS
%
% Ratio of specific heats (1.4 (air), only for compressible flows)
GAMMA_VALUE= 1.4
%
% Specific gas constant (287.87 J/kg*K (air), only for compressible flows)
GAS_CONSTANT= 287.87

% ---------------------- REFERENCE VALUE DEFINITION ---------------------------%
%
% Reference origin for moment computation
REF_ORIGIN_MOMENT_X = 0.00
REF_ORIGIN_MOMENT_Y = 0.00
REF_ORIGIN_MOMENT_Z = 0.00
%
% Reference length for pitching, rolling, and yawing non-dimensional moment
REF_LENGTH= 1.0
%
% Reference area for force coefficients (0 implies automatic calculation)
REF_AREA= 1.0
%
% Flow non-dimensionalization (DIMENSIONAL, FREESTREAM_PRESS_EQ_ONE,
% FREESTREAM_VEL_EQ_MACH, FREESTREAM_VEL_EQ_ONE)
REF_DIMENSIONALIZATION= DIMENSIONAL

% ----------------------- BOUNDARY CONDITION DEFINITION -----------------------%
%
% Marker of the Euler boundary (NONE = no marker)
MARKER_EULER= ( Airfoil )
%
% Marker of the far field (NONE = no marker)
MARKER_FAR= ( Wall )

% Supersonic inlet boundary marker(s) (NONE = no marker)
% Format: (inlet marker, temperature, static pressure, velocity_x,
% velocity_y, velocity_z, ...) i.e. primitive variables specified
MARKER_SUPERSONIC_INLET = ( Inlet, 228.8, 30150.774, 1062.816471, 0.0, 0.0)

% Supersonic outlet boundary marker(s) (NONE = no marker)
MARKER_SUPERSONIC_OUTLET = ( Outlet )

% ------------------------ SURFACES IDENTIFICATION ----------------------------%
%
% Marker(s) of the surface in the surface flow solution file
MARKER_PLOTTING = ( Airfoil )
%
% Marker(s) of the surface where the non-dimensional coefficients are evaluated.
MARKER_MONITORING = ( Airfoil )
%
% Marker(s) of the surface where obj. func. (design problem) will be evaluated
MARKER_DESIGNING = ( Airfoil )

% ------------- COMMON PARAMETERS TO DEFINE THE NUMERICAL METHOD --------------%
%
% Numerical method for spatial gradients (GREEN_GAUSS, WEIGHTED_LEAST_SQUARES)
NUM_METHOD_GRAD= WEIGHTED_LEAST_SQUARES
%
% Objective function in optimization problem (DRAG, LIFT, SIDEFORCE, MOMENT_X,
% MOMENT_Y, MOMENT_Z, EFFICIENCY,
% EQUIVALENT_AREA, NEARFIELD_PRESSURE,
% FORCE_X, FORCE_Y, FORCE_Z, THRUST,
% TORQUE, FREE_SURFACE, TOTAL_HEATFLUX,
% MAXIMUM_HEATFLUX, INVERSE_DESIGN_PRESSURE,
% INVERSE_DESIGN_HEATFLUX)
OBJECTIVE_FUNCTION= DRAG
%
% Courant-Friedrichs-Lewy condition of the finest grid
CFL_NUMBER= 5
% Adaptive CFL number (NO, YES)
CFL_ADAPT= NO
%
% Parameters of the adaptive CFL number (factor down, factor up, CFL min value,
% CFL max value )
CFL_ADAPT_PARAM= ( 0.1, 2.0, 10.0, 1e10 )
%
% Number of total iterations
ITER= 250

% ------------------------ LINEAR SOLVER DEFINITION ---------------------------%
%
% Linear solver for implicit formulations (BCGSTAB, FGMRES)
LINEAR_SOLVER= FGMRES
%
% Preconditioner of the Krylov linear solver (JACOBI, LINELET, LU_SGS)
LINEAR_SOLVER_PREC= ILU
%
% Minimum error of the linear solver for implicit formulations
LINEAR_SOLVER_ERROR= 1E-10
%
% Max number of iterations of the linear solver for the implicit formulation
LINEAR_SOLVER_ITER= 10

% -------------------- FLOW NUMERICAL METHOD DEFINITION -----------------------%
%
% Convective numerical method (JST, LAX-FRIEDRICH, CUSP, ROE, AUSM, HLLC,
% TURKEL_PREC, MSW)
CONV_NUM_METHOD_FLOW= JST
%
% Monotonic Upwind Scheme for Conservation Laws (TVD) in the flow equations.
% Required for 2nd order upwind schemes (NO, YES)
MUSCL_FLOW= YES
%
% Slope limiter (NONE, VENKATAKRISHNAN, VENKATAKRISHNAN_WANG,
% BARTH_JESPERSEN, VAN_ALBADA_EDGE)
SLOPE_LIMITER_FLOW= VENKATAKRISHNAN_WANG
%
% 2nd and 4th order artificial dissipation coefficients
JST_SENSOR_COEFF= ( 0.5, 0.02 )
%
% Time discretization (RUNGE-KUTTA_EXPLICIT, EULER_IMPLICIT, EULER_EXPLICIT)
TIME_DISCRE_FLOW= EULER_IMPLICIT

% ---------------- ADJOINT-FLOW NUMERICAL METHOD DEFINITION -------------------%
%
% Convective numerical method (JST, LAX-FRIEDRICH, ROE)
CONV_NUM_METHOD_ADJFLOW= JST
%
% Monotonic Upwind Scheme for Conservation Laws (TVD) in the adjoint flow equations.
% Required for 2nd order upwind schemes (NO, YES)
MUSCL_ADJFLOW= YES
%
% Slope limiter (NONE, VENKATAKRISHNAN, BARTH_JESPERSEN, VAN_ALBADA_EDGE,
% SHARP_EDGES, WALL_DISTANCE)
SLOPE_LIMITER_ADJFLOW= NONE
%
% Reduction factor of the CFL coefficient in the adjoint problem
CFL_REDUCTION_ADJFLOW= 500
%
% Time discretization (RUNGE-KUTTA_EXPLICIT, EULER_IMPLICIT)
TIME_DISCRE_ADJFLOW= EULER_IMPLICIT

% ----------------------- DESIGN VARIABLE PARAMETERS --------------------------%
%
% Kind of deformation (NO_DEFORMATION, TRANSLATION, ROTATION, SCALE,
% FFD_SETTING, FFD_NACELLE
% FFD_CONTROL_POINT, FFD_CAMBER, FFD_THICKNESS, FFD_TWIST
% FFD_CONTROL_POINT_2D, FFD_CAMBER_2D, FFD_THICKNESS_2D, FFD_TWIST_2D,
% HICKS_HENNE, SURFACE_BUMP)
DV_KIND= HICKS_HENNE
%
% Marker of the surface in which we are going apply the shape deformation
DV_MARKER= ( Airfoil )
%
% Parameters of the shape deformation
% - NO_DEFORMATION ( 1.0 )
% - TRANSLATION ( x_Disp, y_Disp, z_Disp ), as a unit vector
% - ROTATION ( x_Orig, y_Orig, z_Orig, x_End, y_End, z_End )
% - SCALE ( 1.0 )
% - ANGLE_OF_ATTACK ( 1.0 )
% - FFD_SETTING ( 1.0 )
% - FFD_CONTROL_POINT ( FFD_BoxTag, i_Ind, j_Ind, k_Ind, x_Disp, y_Disp, z_Disp )
% - FFD_NACELLE ( FFD_BoxTag, rho_Ind, theta_Ind, phi_Ind, rho_Disp, phi_Disp )
% - FFD_GULL ( FFD_BoxTag, j_Ind )
% - FFD_ANGLE_OF_ATTACK ( FFD_BoxTag, 1.0 )
% - FFD_CAMBER ( FFD_BoxTag, i_Ind, j_Ind )
% - FFD_THICKNESS ( FFD_BoxTag, i_Ind, j_Ind )
% - FFD_TWIST ( FFD_BoxTag, j_Ind, x_Orig, y_Orig, z_Orig, x_End, y_End, z_End )
% - FFD_CONTROL_POINT_2D ( FFD_BoxTag, i_Ind, j_Ind, x_Disp, y_Disp )
% - FFD_CAMBER_2D ( FFD_BoxTag, i_Ind )
% - FFD_THICKNESS_2D ( FFD_BoxTag, i_Ind )
% - FFD_TWIST_2D ( FFD_BoxTag, x_Orig, y_Orig )
% - HICKS_HENNE ( Lower Surface (0)/Upper Surface (1)/Only one Surface (2), x_Loc )
% - SURFACE_BUMP ( x_Start, x_End, x_Loc )
DV_PARAM= ( 1, 0.5 )
%
% Value of the shape deformation
DV_VALUE= 0.01

% ------------------------ GRID DEFORMATION PARAMETERS ------------------------%
%
% Number of smoothing iterations for FEA mesh deformation
DEFORM_LINEAR_SOLVER_ITER= 500
%
% Number of nonlinear deformation iterations (surface deformation increments)
DEFORM_NONLINEAR_ITER= 1
%
% Minimum residual criteria for the linear solver convergence of grid deformation
DEFORM_LINEAR_SOLVER_ERROR= 1E-14
%
% Print the residuals during mesh deformation to the console (YES, NO)
DEFORM_CONSOLE_OUTPUT= YES
%
% Type of element stiffness imposed for FEA mesh deformation (INVERSE_VOLUME,
% WALL_DISTANCE, CONSTANT_STIFFNESS)
DEFORM_STIFFNESS_TYPE= INVERSE_VOLUME

% --------------------------- CONVERGENCE PARAMETERS --------------------------%
%
CONV_FIELD= RMS_DENSITY
%
% Min value of the residual (log10 of the residual)
CONV_RESIDUAL_MINVAL= -8
%
% Start Cauchy criteria at iteration number
CONV_STARTITER= 10
%
% Number of elements to apply the criteria
CONV_CAUCHY_ELEMS= 100
%
% Epsilon to control the series convergence
CONV_CAUCHY_EPS= 1E-6
%
SCREEN_OUTPUT=(INNER_ITER, WALL_TIME, RMS_DENSITY, LIFT, DRAG, CAUCHY_SENS_PRESS, CAUCHY_DRAG RMS_ADJ_DENSITY RMS_ADJ_ENERGY, MACH_NUMBER)

% ------------------------- INPUT/OUTPUT INFORMATION --------------------------%
% Mesh input file
MESH_FILENAME= 3D-Test.su2
%
% Mesh input file format (SU2, CGNS, NETCDF_ASCII)
MESH_FORMAT= SU2
%
% Mesh output file
MESH_OUT_FILENAME= mesh_out.su2
%
% Restart flow input file
SOLUTION_FILENAME= solution_flow.dat
%
% Restart adjoint input file
SOLUTION_ADJ_FILENAME= solution_adj.dat
%
% Output file format (TECPLOT, PARAVIEW, TECPLOT_BINARY)
TABULAR_FORMAT= CSV
%
% Output file convergence history (w/o extension)
CONV_FILENAME= Data
%
% Output file restart flow
% RESTART_FILENAME= Restart-Flow.dat
%
% Output file restart adjoint
RESTART_ADJ_FILENAME= restart_adj.dat
%
% Output file flow (w/o extension) variables
VOLUME_FILENAME= PARAVIEW-Simulation
%
% Output file adjoint (w/o extension) variables
VOLUME_ADJ_FILENAME= adjoint
%
% Output Objective function gradient (using continuous adjoint)
GRAD_OBJFUNC_FILENAME= of_grad.dat
%
% Output file surface flow coefficient (w/o extension)
% SURFACE_FILENAME= surface_flow
%
% Output file surface adjoint coefficient (w/o extension)
SURFACE_ADJ_FILENAME= surface_adjoint
%
% Writing solution file frequency
OUTPUT_WRT_FREQ= 250

% --------------------- OPTIMAL SHAPE DESIGN DEFINITION -----------------------%
% Available flow based objective functions or constraint functions
% DRAG, LIFT, SIDEFORCE, EFFICIENCY,
% FORCE_X, FORCE_Y, FORCE_Z,
% MOMENT_X, MOMENT_Y, MOMENT_Z,
% THRUST, TORQUE, FIGURE_OF_MERIT,
% EQUIVALENT_AREA, NEARFIELD_PRESSURE,
% TOTAL_HEATFLUX, MAXIMUM_HEATFLUX,
% INVERSE_DESIGN_PRESSURE, INVERSE_DESIGN_HEATFLUX,
%
% Available geometrical based objective functions or constraint functions
% AIRFOIL_AREA, AIRFOIL_THICKNESS, AIRFOIL_CHORD, AIRFOIL_TOC, AIRFOIL_AOA,
% WING_VOLUME, WING_MIN_THICKNESS, WING_MAX_THICKNESS, WING_MAX_CHORD, WING_MIN_TOC, WING_MAX_TWIST, WING_MAX_CURVATURE, WING_MAX_DIHEDRAL
% STATION#_WIDTH, STATION#_AREA, STATION#_THICKNESS, STATION#_CHORD, STATION#_TOC,
% STATION#_TWIST (where # is the index of the station defined in GEO_LOCATION_STATIONS)
%
% Available design variables
% HICKS_HENNE ( 1, Scale | Mark. List | Lower(0)/Upper(1) side, x_Loc )
% NACA_4DIGITS ( 4, Scale | Mark. List | 1st digit, 2nd digit, 3rd and 4th digit )
% TRANSLATION ( 5, Scale | Mark. List | x_Disp, y_Disp, z_Disp )
% ROTATION ( 6, Scale | Mark. List | x_Axis, y_Axis, z_Axis, x_Turn, y_Turn, z_Turn )
% FFD_CONTROL_POINT_2D ( 15, Scale | Mark. List | FFD_Box_ID, i_Ind, j_Ind, x_Mov, y_Mov )
% FFD_CAMBER_2D ( 16, Scale | Mark. List | FFD_Box_ID, i_Ind )
% FFD_THICKNESS_2D ( 17, Scale | Mark. List | FFD_Box_ID, i_Ind )
%
% Optimization objective function with scaling factor
% ex= Objective * Scale
OPT_OBJECTIVE= DRAG * 0.001
%
% Optimization constraint functions with scaling factors, separated by semicolons
% ex= (Objective = Value ) * Scale, use '>','<','='
OPT_CONSTRAINT= ( LIFT > 0.328188 ) * 0.001; ( MOMENT_Z > 0.034068 ) * 0.001; ( AIRFOIL_THICKNESS > 0.11 ) * 0.001
%

% Optimization design variables, separated by semicolons
DEFINITION_DV= ( 30, 1.0 | Airfoil | 0, 0.05 ); ( 30, 1.0 | airfoil | 0, 0.10 ); ( 30, 1.0 | airfoil | 0, 0.15 ); ( 30, 1.0 | airfoil | 0, 0.20 ); ( 30, 1.0 | airfoil | 0, 0.25 ); ( 30, 1.0 | airfoil | 0, 0.30 ); ( 30, 1.0 | airfoil | 0, 0.35 ); ( 30, 1.0 | airfoil | 0, 0.40 ); ( 30, 1.0 | airfoil | 0, 0.45 ); ( 30, 1.0 | airfoil | 0, 0.50 ); ( 30, 1.0 | airfoil | 0, 0.55 ); ( 30, 1.0 | airfoil | 0, 0.60 ); ( 30, 1.0 | airfoil | 0, 0.65 ); ( 30, 1.0 | airfoil | 0, 0.70 ); ( 30, 1.0 | airfoil | 0, 0.75 ); ( 30, 1.0 | airfoil | 0, 0.80 ); ( 30, 1.0 | airfoil | 0, 0.85 ); ( 30, 1.0 | airfoil | 0, 0.90 ); ( 30, 1.0 | airfoil | 0, 0.95 ); ( 30, 1.0 | airfoil | 1, 0.05 ); ( 30, 1.0 | airfoil | 1, 0.10 ); ( 30, 1.0 | airfoil | 1, 0.15 ); ( 30, 1.0 | airfoil | 1, 0.20 ); ( 30, 1.0 | airfoil | 1, 0.25 ); ( 30, 1.0 | airfoil | 1, 0.30 ); ( 30, 1.0 | airfoil | 1, 0.35 ); ( 30, 1.0 | airfoil | 1, 0.40 ); ( 30, 1.0 | airfoil | 1, 0.45 ); ( 30, 1.0 | airfoil | 1, 0.50 ); ( 30, 1.0 | airfoil | 1, 0.55 ); ( 30, 1.0 | airfoil | 1, 0.60 ); ( 30, 1.0 | airfoil | 1, 0.65 ); ( 30, 1.0 | airfoil | 1, 0.70 ); ( 30, 1.0 | airfoil | 1, 0.75 ); ( 30, 1.0 | airfoil | 1, 0.80 ); ( 30, 1.0 | airfoil | 1, 0.85 ); ( 30, 1.0 | airfoil | 1, 0.90 ); ( 30, 1.0 | airfoil | 1, 0.95 )

[wallym]

Hi Moose,

The hypersonic portion is probably partially misleading. The temperatures are fairly low in the separation region so the Mach will be higher. What is the expected behavior behind the body?

Can you post the ending portion of the screen output? Are there non-physical points?

In this case, with a large separation region there's a few things I can think of:
1.) Better mesh refinement in the region behind the body
2.) Run at lower CFL/go explicit instead
3.) Start with MUSCL=NO and then restart later with MUSCL=YES
4.) Run unsteady -> I imagine that there could be oscillations in the flow.

Other than that, your config file looks good.
Let us know if any other suggestions work.

Wally

[Moose21]

Hey Wally,

Thank you for the suggestion, ill go ahead and try them out.