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#1 |
New Member
Süleyman
Join Date: Dec 2024
Posts: 1
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Hello, I am working on ramjet inlet cfd but it says "SU2 has diverged (NaN detected)." Could you help me to use proper methods and options to solve my problem, what should I change in my settings. Analysis will run at 3 mach I am trying to find optimum back pressure for externally compressed ramjet inlet. Also what should be the boundary layer settings?
% ------------- DIRECT, ADJOINT, AND LINEARIZED PROBLEM DEFINITION ------------% % % Physical governing equations (EULER, NAVIER_STOKES, % WAVE_EQUATION, HEAT_EQUATION, FEM_ELASTICITY, % POISSON_EQUATION) SOLVER= RANS % FLUID_MODEL= STANDARD_AIR % Specify turbulence model (NONE, SA, SA_NEG, SST, SA_E, SA_COMP, SA_E_COMP, SST_SUST) % Mathematical problem (DIRECT, CONTINUOUS_ADJOINT) MATH_PROBLEM= DIRECT % % Restart solution (NO, YES) RESTART_SOL= NO % % System of measurements (SI, US) % International system of units (SI): ( meters, kilograms, Kelvins, % Newtons = kg m/s^2, Pascals = N/m^2, % Density = kg/m^3, Speed = m/s, % Equiv. Area = m^2 ) % United States customary units (US): ( inches, slug, Rankines, lbf = slug ft/s^2, % psf = lbf/ft^2, Density = slug/ft^3, % Speed = ft/s, Equiv. Area = ft^2 ) SYSTEM_MEASUREMENTS= SI % ----------- COMPRESSIBLE AND INCOMPRESSIBLE FREE-STREAM DEFINITION ----------% % % Mach number (non-dimensional, based on the free-stream values) MACH_NUMBER= 3 % % Reynolds number (non-dimensional, based on the free-stream values) REYNOLDS_NUMBER= 46.268E6 % Reynolds length (1 m, 1 inch by default) REYNOLDS_LENGTH= 1 % % Angle of attack (degrees) AOA= 0.0 % % Side-slip angle (degrees) SIDESLIP_ANGLE= 0.0 % % Free-stream pressure (101325.0 N/m^2 by default, only Euler flows) FREESTREAM_PRESSURE= 101325 % % Free-stream temperature (288.15 K by default) FREESTREAM_TEMPERATURE= 300.0 INIT_OPTION= REYNOLDS FREESTREAM_TURBULENCEINTENSITY= 0.01 FREESTREAM_OPTION= TEMPERATURE_FS % ---------------------- 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 % % Reference area for force coefficients (0 implies automatic calculation) REF_AREA= 0 % -------------------- BOUNDARY CONDITION DEFINITION --------------------------% % % Navier-Stokes (no-slip), constant heat flux wall marker(s) (NONE = no marker) % Format: ( marker name, constant heat flux (J/m^2), ... ) MARKER_HEATFLUX= ( wall,0,axis,0) MARKER_FAR= ( far_field ) % % Supersonic inlet boundary marker(s) (NONE = no marker) % Total Conditions: (inlet marker, temperature, static pressure, velocity_x, % velocity_y, velocity_z, ... ), i.e. all variables specified. MARKER_SUPERSONIC_INLET= ( inlet, 300.0, 101325, 1029, 0.0, 0.0 ) % % Outlet boundary marker(s) (NONE = no marker) % Format: ( outlet marker, back pressure (static), ... ) MARKER_OUTLET= ( outlet,500000) %MARKER_PRESSURE= ( outlet, 2400000 ) % % Marker(s) of the surface to be plotted or designed MARKER_PLOTTING= ( wall ) % % Marker(s) of the surface where the functional (Cd, Cl, etc.) will be evaluated MARKER_MONITORING= ( wall ) MARKER_SUPERSONIC_OUTLET= ( far_field ) % Symmetry boundary marker(s) (NONE = no marker) MARKER_SYM=(axis) %MARKER_EULER=(axis) % % --------------------------- VISCOSITY MODEL ---------------------------------% % % Viscosity model (SUTHERLAND, CONSTANT_VISCOSITY). VISCOSITY_MODEL= SUTHERLAND % % Sutherland Viscosity Ref (1.716E-5 default value for AIR SI) MU_REF= 1.716E-5 % % Sutherland Temperature Ref (273.15 K default value for AIR SI) MU_T_REF= 273.15 % % Sutherland constant (110.4 default value for AIR SI) SUTHERLAND_CONSTANT= 110.4 % % ------------- COMMON PARAMETERS DEFINING THE NUMERICAL METHOD ---------------% % %NUM_METHOD_GRAD_RECON= LEAST_SQUARES % % Courant-Friedrichs-Lewy condition of the finest grid CFL_NUMBER= 2 % % 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, 5.0, 1e10) % % Runge-Kutta alpha coefficients RK_ALPHA_COEFF= ( 0.66667, 0.66667, 1.000000 ) % % Number of total iterations ITER= 5000 % % Linear solver for the implicit formulation (BCGSTAB, FGMRES) LINEAR_SOLVER= FGMRES % % Preconditioner of the Krylov linear solver (ILU, JACOBI, LINELET, LU_SGS) LINEAR_SOLVER_PREC= ILU % % Min error of the linear solver for the implicit formulation LINEAR_SOLVER_ERROR= 1E-6 % % Max number of iterations of the linear solver for the implicit formulation LINEAR_SOLVER_ITER= 20 % -------------------------- MULTIGRID PARAMETERS -----------------------------% % % Multi-Grid Levels (0 = no multi-grid) MGLEVEL= 0 % % Multi-grid cycle (V_CYCLE, W_CYCLE, FULLMG_CYCLE) MGCYCLE= W_CYCLE % % Multi-grid pre-smoothing level MG_PRE_SMOOTH= ( 1, 2, 3, 3 ) % % Multi-grid post-smoothing level MG_POST_SMOOTH= ( 0, 0, 0, 0 ) % % Jacobi implicit smoothing of the correction MG_CORRECTION_SMOOTH= ( 0, 0, 0, 0 ) % % Damping factor for the residual restriction MG_DAMP_RESTRICTION= 1 % % Damping factor for the correction prolongation MG_DAMP_PROLONGATION= 1 % -------------------- FLOW NUMERICAL METHOD DEFINITION -----------------------% % % Monotonic Upwind Scheme for Conservation Laws (TVD) in the flow equations. % Required for 2nd order upwind schemes (NO, YES) MUSCL_FLOW= NO % % Slope limiter (NONE, VENKATAKRISHNAN, VENKATAKRISHNAN_WANG, % BARTH_JESPERSEN, VAN_ALBADA_EDGE) SLOPE_LIMITER_FLOW=VENKATAKRISHNAN % % Coefficient for the limiter (smooth regions) VENKAT_LIMITER_COEFF= 0.006 % % 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 % --------------------------- CONVERGENCE PARAMETERS --------------------------% % % Convergence criteria (CAUCHY, RESIDUAL) CONV_FIELD= RMS_DENSITY % % Min value of the residual (log10 of the residual) CONV_RESIDUAL_MINVAL= -8 % % Start convergence 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-10 % -------------------- TURBULENT NUMERICAL METHOD DEFINITION ------------------% % % Convective numerical method (SCALAR_UPWIND) CONV_NUM_METHOD_TURB= SCALAR_UPWIND % % Time discretization (EULER_IMPLICIT) TIME_DISCRE_TURB= EULER_IMPLICIT % % Reduction factor of the CFL coefficient in the turbulence problem CFL_REDUCTION_TURB= 1.0 % ------------------------- INPUT/OUTPUT INFORMATION --------------------------% % % Mesh input file %MESH_FILENAME= backp.su2 MESH_FILENAME= mach3_con.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 tabular format (CSV, TECPLOT) TABULAR_FORMAT= CSV % % Output file convergence history (w/o extension) CONV_FILENAME= history % % 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= flow_con_3M_500KPa % % 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 % % % Screen output SCREEN_OUTPUT=(INNER_ITER, WALL_TIME, RMS_DENSITY, RMS_ENERGY, LIFT, DRAG) % Writing frequency for screen output SCREEN_WRT_FREQ_INNER= 100 % SCREEN_WRT_FREQ_OUTER= 100 % SCREEN_WRT_FREQ_TIME= 100 % % Writing frequency for history output HISTORY_WRT_FREQ_INNER= 10 % HISTORY_WRT_FREQ_OUTER= 10 % HISTORY_WRT_FREQ_TIME= 10 % ----------------------- DESIGN VARIABLE PARAMETERS --------------------------% % % % Kind of deformation (NO_DEfFORMATION, SCALE_GRID, TRANSLATE_GRID, ROTATE_GRID, % 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, SURFACE_FILE) DV_KIND= SCALE_GRID % % - NO_DEFORMATION ( 1.0 ) % - TRANSLATE_GRID ( x_Disp, y_Disp, z_Disp ), as a unit vector % - ROTATE_GRID ( x_Orig, y_Orig, z_Orig, x_End, y_End, z_End ) axis, DV_VALUE in deg. % - SCALE_GRID ( 1.0 ) DV_PARAM= ( 1.0 ) % % Value of the deformation DV_VALUE= 10.0 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5 AXISYMMETRIC= YES % Convective numerical method (JST, LAX-FRIEDRICH, CUSP, ROE, AUSM, HLLC, % TURKEL_PREC, MSW) CONV_NUM_METHOD_FLOW= AUSM % Specify turbulence model (NONE, SA, SA_NEG, SST, SA_E, SA_COMP, SA_E_COMP, SST_SUST) KIND_TURB_MODEL=SST %SST_OPTIONS=V2003m %SA_OPTIONS=EDWARDS % Numerical method for spatial gradients (GREEN_GAUSS, LEAST_SQUARES, % WEIGHTED_LEAST_SQUARES) NUM_METHOD_GRAD=WEIGHTED_LEAST_SQUARES and this is the .geo file: // Gmsh project created on Thu Dec 19 00:17:59 2024 SetFactory("OpenCASCADE"); //+ Point(1) = {0, 0, 0, 1.0}; //+ Point(2) = {0.5, 0, 0, 1.0}; //+ Point(3) = {0.75, 0.053, 0, 1.0}; //+ Point(4) = {1, 0.1129, 0, 1.0}; //+ Point(5) = {1.25, 0.189, 0, 1.0}; //+ Point(6) = {1.4, 0.255, 0, 1.0}; //+ Point(7) = {1.5, 0.26, 0, 1.0}; //+ Point(8) = {1.6, 0.26, 0, 1.0}; //+ Point(9) = {2, 0.26, 0, 1.0}; //+ Point(10) = {3, 0.15 ,0, 1.0}; //+ Point(11) = {3, 0.4247, 0, 1.0}; //+ Point(12) = {1.4, 0.4247, 0, 1.0}; //+ Point(13) = {2, 0.5, 0, 1.0}; //+ Point(14) = {3, 0.5, 0, 1.0}; //+ Point(15) = {3, 1, 0, 1.0}; //+ Point(16) = {0, 1, 0, 1.0}; //+ Line(1) = {1, 2}; //+ Line(2) = {2, 3}; //+ Line(3) = {3, 4}; //+ Line(4) = {4, 5}; //+ Line(5) = {5, 6}; //+ Line(6) = {6, 7}; //+ Line(7) = {7, 8}; //+ Line(8) = {8, 9}; //+ Line(9) = {9, 10}; //+ Line(10) = {10, 11}; //+ Line(11) = {11, 12}; //+ Line(12) = {12, 13}; //+ Line(13) = {13, 14}; //+ Line(14) = {14, 15}; //+ Line(15) = {15, 16}; //+ Line(16) = {16, 1}; //+ Physical Curve("inlet") = {16}; //+ Physical Curve("far_field") = {15, 14}; //+ Physical Curve("outlet") = {10}; //+ Physical Curve("axis") = {1}; //+ Physical Curve("wall") = {13, 12, 11, 9, 8, 7, 6, 5, 4, 3, 2}; //+ Transfinite Curve { 11} = 201 Using Progression 1; //+ Transfinite Curve {9, 13,16} = 101 Using Progression 1; //+ Transfinite Curve {1, 8,14} = 51 Using Progression 1; //+ Transfinite Curve {2, 3, 4, 5} = 31 Using Progression 1; Transfinite Curve {6,7} = 21 Using Progression 1; //+ Transfinite Curve {12} = 71 Using Progression 1; //+ Transfinite Curve {13} = 81 Using Progression 1; //+ //+ Transfinite Curve {15} = 251 Using Progression 1; //+ Transfinite Curve {10} = 61 Using Progression 1; //+ //+ Curve Loop(1) = {16, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}; //+ Plane Surface(1) = {1}; Field[1] = BoundaryLayer; Field[1].EdgesList = {12, 11, 9, 8, 7, 6, 5, 4, 3, 2,13,1,10}; // The "wall" line ID Field[1].hfar = 0.005; Field[1].hwall_n = 0.0005; Field[1].thickness = 0.005; Field[1].ratio = 1.2; Field[1].IntersectMetrics = 0; Field[1].Quads = 1; BoundaryLayer Field = 1; |
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#2 |
Senior Member
bigfoot
Join Date: Dec 2011
Location: Netherlands
Posts: 716
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Do you really have a 3 meter long ramjet?
Because that size might give you some difficulty. If you have viscous flow you need to properly resolve the boundary layer, and this requires a lot of cells. It probably diverges because your mesh is not fine enough to properly resolve this. I think this is a mistake, maybe you can check what the actual dimensions of your setup are, it is probably smaller than what you have right now. I also see that you have defined transfinite lines but no transfinite surfaces. A transfinite surface will get you a very well defined, structured mesh of a higher quality than the unstructured triangulation that you have right now. There is also a mistake in your setup, and in SU2 because it did not complain about it: you define your boundary "far_field" as a far-field as well as a supersonic outlet. It should be one or the other., probably far-field is fine. Your marker_outlet(outlet) should probably be marker_supersonic_outlet(outlet) |
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Tags |
ramjet, ramp, su2, supersonic |
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