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"NaN detected" in the simulation.

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Old   November 27, 2023, 01:56
Default "NaN detected" in the simulation.
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Zhang
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Hi, SU2ers

I have encountered the issue of "NaN detected" in my simulation previously and successfully addressed it by implementing a first-order wind scheme, reducing the CFL number, and employing other strategies. As a result, my simulation progressed smoothly to a certain extent. However, the same solutions proved ineffective on this occasion.

The mesh I am using represents an aircraft inlet with a sidewall. Interestingly, the simulation converges well in the absence of a sidewall. However, when the sidewall is present, the calculation diverges, leading to the detection of "NaN."

I have attached my configuration file below for your reference. I would sincerely appreciate any assistance or insights you may provide on this matter.

Thank you very much for your help.

Best regards,
Zhang

----------------------------------------------------------------------------------------------------------------------
SOLVER= RANS
KIND_TURB_MODEL=SST
SST_OPTIONS=V2003m
Mathematical problem (DIRECT, CONTINUOUS_ADJOINT)
MATH_PROBLEM= DIRECT
%
% Axisymmetric simulation, only compressible flows (NO, YES)
AXISYMMETRIC= NO
%
% Restart solution (NO, YES)
RESTART_SOL= NO
SYSTEM_MEASUREMENTS= SI
ITER = 30000
% Mach number (non-dimensional, based on the free-stream values) the only parameter of the computation!!!
MACH_NUMBER= 6
%
% Angle of attack (degrees, only for compressible flows)
AOA= 0
%
% Side-slip angle (degrees, only for compressible flows)
SIDESLIP_ANGLE= 0.0
%
% Init option to choose between Reynolds (default) or thermodynamics quantities
% for initializing the solution (REYNOLDS, TD_CONDITIONS)
INIT_OPTION= REYNOLDS
%
% Free-stream option to choose between density and temperature (default) for
% initializing the solution (TEMPERATURE_FS, DENSITY_FS)
FREESTREAM_OPTION= TEMPERATURE_FS
%
% Free-stream pressure (101325.0 N/m^2, 2116.216 psf by default)
FREESTREAM_PRESSURE= 1998
%
% Free-stream temperature (288.15 K, 518.67 R by default)
FREESTREAM_TEMPERATURE= 223.1
FREESTREAM_DENSITY= 0.0312
%
% Reynolds number (non-dimensional, based on the free-stream values)
REYNOLDS_NUMBER= 3735662
%
% Reynolds length (1 m, 1 inch by default)
REYNOLDS_LENGTH= 1.0
% Reference origin for moment computation (m or in)
REF_ORIGIN_MOMENT_X = 0.25
REF_ORIGIN_MOMENT_Y = 0.00
REF_ORIGIN_MOMENT_Z = 0.00
%
% Reference length for moment non-dimensional coefficients (m or in)
REF_LENGTH= 1.0
%
% Reference area for non-dimensional force coefficients (0 implies automatic
% calculation) (m^2 or in^2)
REF_AREA= 1.0
%
% Aircraft semi-span (0 implies automatic calculation) (m or in)
SEMI_SPAN= 0.0
% Fluid model (STANDARD_AIR, IDEAL_GAS, VW_GAS, PR_GAS,
% CONSTANT_DENSITY, INC_IDEAL_GAS)
FLUID_MODEL= STANDARD_AIR
%
% Ratio of specific heats (1.4 default and the value is hardcoded
% for the model STANDARD_AIR, compressible only)
GAMMA_VALUE= 1.4
%
% Specific gas constant (287.058 J/kg*K default and this value is hardcoded
% for the model STANDARD_AIR, compressible only)
GAS_CONSTANT= 287.058
%
% Critical Temperature (131.00 K by default)
CRITICAL_TEMPERATURE= 131.00
%
% Critical Pressure (3588550.0 N/m^2 by default)
CRITICAL_PRESSURE= 3588550.0
%
% Acentri factor (0.035 (air))
ACENTRIC_FACTOR= 0.035
%
% Specific heat at constant pressure, Cp (1004.703 J/kg*K (air)).
% Incompressible fluids with energy eqn. only (CONSTANT_DENSITY, INC_IDEAL_GAS).
SPECIFIC_HEAT_CP= 1004.703
%
% Molecular weight for an incompressible ideal gas (28.96 g/mol (air) default)
% Incompressible fluids with energy eqn. only (CONSTANT_DENSITY, INC_IDEAL_GAS).
MOLECULAR_WEIGHT= 28.96
%
% Thermal expansion coefficient (0.00347 K^-1 (air))
% Used with Boussinesq approx. (incompressible, BOUSSINESQ density model only)
THERMAL_EXPANSION_COEFF= 0.00347
% Viscosity model (SUTHERLAND, CONSTANT_VISCOSITY).
VISCOSITY_MODEL= SUTHERLAND
%
% Molecular Viscosity that would be constant (1.716E-5 by default)
MU_CONSTANT= 1.716E-5
%
% 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
% Conductivity model (CONSTANT_CONDUCTIVITY, CONSTANT_PRANDTL).
CONDUCTIVITY_MODEL= CONSTANT_PRANDTL
%
% Molecular Thermal Conductivity that would be constant (0.0257 by default)
DIFFUSIVITY_CONSTANT= 0.0257
%
% Laminar Prandtl number (0.72 (air), only for CONSTANT_PRANDTL)
PRANDTL_LAM= 0.72
%
% Turbulent Prandtl number (0.9 (air), only for CONSTANT_PRANDTL)
PRANDTL_TURB= 0.90
% Navier-Stokes (no-slip), constant heat flux wall marker(s) (NONE = no marker)
% Format: ( marker name, constant heat flux (J/m^2), ... )
MARKER_HEATFLUX= ( RAMP, 0.0, COWL,0.0, UPWALL,0.0, SIDEWALL,0.0)
% Far-field boundary marker(s) (NONE = no marker)
MARKER_FAR= ( FAR )
%
% Symmetry boundary marker(s) (NONE = no marker)
MARKER_SYM= ( SYM1, SYM2 )
MARKER_OUTLET= ( OUT, 1998, FAROUT, 1998 )
% Marker(s) of the surface in the surface flow solution file
MARKER_PLOTTING = ( RAMP )
%
% Marker(s) of the surface where the non-dimensional coefficients are evaluated.
MARKER_MONITORING = ( OUT )
%
% Viscous wall markers for which wall functions must be applied. (NONE = no marker)
% Format: ( marker name, wall function type, ... )
MARKER_WALL_FUNCTIONS= ( NONE, NO_WALL_FUNCTION )
%
% Marker(s) of the surface where custom thermal BC's are defined.
MARKER_PYTHON_CUSTOM = ( NONE )
%
% Marker(s) of the surface where obj. func. (design problem) will be evaluated
MARKER_DESIGNING = ( OUT )
%
% Marker(s) of the surface that is going to be analyzed in detail (massflow, average pressure, distortion, etc)
MARKER_ANALYZE = ( OUT )
%
% Method to compute the average value in MARKER_ANALYZE (AREA, MASSFLUX).
MARKER_ANALYZE_AVERAGE = MASSFLUX
% Marker(s) of the surface where geometrical based function will be evaluated
GEO_MARKER= ( NONE )
%
% Description of the geometry to be analyzed (AIRFOIL, WING)
GEO_DESCRIPTION= AIRFOIL
%
% Coordinate of the stations to be analyzed
GEO_LOCATION_STATIONS= (0.0, 0.5, 1.0)
%
% Geometrical bounds (Y coordinate) for the wing geometry analysis or
% fuselage evaluation (X coordinate)
GEO_BOUNDS= (1.5, 3.5)
%
% Plot loads and Cp distributions on each airfoil section
GEO_PLOT_STATIONS= NO
%
% Number of section cuts to make when calculating wing geometry
GEO_NUMBER_STATIONS= 25
%
% Geometrical evaluation mode (FUNCTION, GRADIENT)
GEO_MODE= FUNCTION
% Numerical method for spatial gradients (GREEN_GAUSS, WEIGHTED_LEAST_SQUARES)
NUM_METHOD_GRAD= GREEN_GAUSS
%
% CFL number (initial value for the adaptive CFL number)
CFL_NUMBER= 0.5
%
% 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= ( 1.5, 0.5, 1.25, 50.0 )
%
% Maximum Delta Time in local time stepping simulations
MAX_DELTA_TIME= 1E6
%
% Runge-Kutta alpha coefficients
RK_ALPHA_COEFF= ( 0.66667, 0.66667, 1.000000 )
% 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
%
% Monotonic Upwind Scheme for Conservation Laws (TVD) in the turbulence equations.
% Required for 2nd order upwind schemes (NO, YES)
MUSCL_TURB= NO
%
% Slope limiter (NONE, VENKATAKRISHNAN, VENKATAKRISHNAN_WANG,
% BARTH_JESPERSEN, VAN_ALBADA_EDGE)
SLOPE_LIMITER_TURB= VENKATAKRISHNAN
%

% Coefficient for the Venkat's limiter (upwind scheme). A larger values decrease
% the extent of limiting, values approaching zero cause
% lower-order approximation to the solution (0.05 by default)
VENKAT_LIMITER_COEFF= 0.05
%
% Coefficient for the adjoint sharp edges limiter (3.0 by default).
% ADJ_SHARP_LIMITER_COEFF= 3.0
%
% Freeze the value of the limiter after a number of iterations
LIMITER_ITER= 999999
%

% 1st order artificial dissipation coefficients for
% the Lax–Friedrichs method ( 0.15 by default )
LAX_SENSOR_COEFF= 0.15
%
% 2nd and 4th order artificial dissipation coefficients for
% the JST method ( 0.5, 0.02 by default )
JST_SENSOR_COEFF= ( 0.5, 0.02 )
%
% 1st order artificial dissipation coefficients for
% the adjoint Lax–Friedrichs method ( 0.15 by default )
% ADJ_LAX_SENSOR_COEFF= 0.15
%
% 2nd, and 4th order artificial dissipation coefficients for
% the adjoint JST method ( 0.5, 0.02 by default )
% ADJ_JST_SENSOR_COEFF= ( 0.5, 0.02 )
LINEAR_SOLVER= FGMRES
%
% Preconditioner of the Krylov linear solver (ILU, LU_SGS, LINELET, JACOBI)
LINEAR_SOLVER_PREC= LU_SGS
%
% Linael solver ILU preconditioner fill-in level (0 by default)
LINEAR_SOLVER_ILU_FILL_IN= 0
%
% Minimum error of the linear solver for implicit formulations
LINEAR_SOLVER_ERROR= 0.1
%
% Max number of iterations of the linear solver for the implicit formulation
LINEAR_SOLVER_ITER= 5
% Convective numerical method (JST, LAX-FRIEDRICH, CUSP, ROE, AUSM, HLLC,
% TURKEL_PREC, MSW, FDS)
CONV_NUM_METHOD_FLOW= ROE
%
% Roe Low Dissipation function for Hybrid RANS/LES simulations (FD, NTS, NTS_DUCROS)
%ROE_LOW_DISSIPATION= FD
%
% Post-reconstruction correction for low Mach number flows (NO, YES)
LOW_MACH_CORR= NO
%
% Roe-Turkel preconditioning for low Mach number flows (NO, YES)
LOW_MACH_PREC= NO
%
% Entropy fix coefficient (0.0 implies no entropy fixing, 1.0 implies scalar
% artificial dissipation)
ENTROPY_FIX_COEFF= 0.0
%
% Time discretization (RUNGE-KUTTA_EXPLICIT, EULER_IMPLICIT, EULER_EXPLICIT)
TIME_DISCRE_FLOW= EULER_IMPLICIT
%
% Relaxation coefficient
RELAXATION_FACTOR_ADJOINT= 0.95
% Convective numerical method (SCALAR_UPWIND)
CONV_NUM_METHOD_TURB= SCALAR_UPWIND
%
% Time discretization (EULER_IMPLICIT)
TIME_DISCRE_TURB= EULER_IMPLICIT
%
% Reduction factor of the coefficient in the turbulence problem
CFL_REDUCTION_TURB= 1.0
CONV_RESIDUAL_MINVAL= -10
CONV_STARTITER= 0
CONV_CAUCHY_ELEMS= 100
CONV_CAUCHY_EPS= 0.1
OUTPUT_FILES= (RESTART, TECPLOT)
% list of writing frequencies corresponding to the list in OUTPUT_FILES
OUTPUT_WRT_FREQ= 500, 5
%
HISTORY_WRT_FREQ_OUTER= 50
%
HISTORY_WRT_FREQ_TIME= 50
% Mesh input file
MESH_FILENAME= inlet.cgns
%
% Mesh input file format (SU2, CGNS, NETCDF_ASCII)
MESH_FORMAT= CGNS
%
% Mesh output file
MESH_OUT_FILENAME= mesh_out.su2
%
% Restart flow input file
SOLUTION_FILENAME= restart_flow.dat
%
% Restart adjoint input file
SOLUTION_ADJ_FILENAME= solution_adj.dat
%
% Output file format (PARAVIEW, TECPLOT, STL)
TABULAR_FORMAT= TECPLOT
%
% 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
VOLUME_OUTPUT=(COORDINATES, SOLUTION, PRIMITIVE, MEAN_DENSITY, MEAN_VELOCITY-X, MEAN_VELOCITY-Y, MEAN_VELOCITY-Z, MEAN_PRESSURE)
%
% 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=(TIME_ITER, INNER_ITER, LIFT, DRAG, TOTAL_HEATFLUX, SURFACE_STATIC_PRESSURE)
%
% History output groups (use 'SU2_CFD -d <config_file>' to view list of available fields)
HISTORY_OUTPUT= (ITER, SURFACE_MACH, SURFACE_MASSFLOW, SURFACE_STATIC_PRESSURE )
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Old   November 29, 2023, 15:42
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bigfoot
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Hi, do you have the mesh available?
What do you mean with aircraft inlet? You mean the inlet of the engine?
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Old   November 29, 2023, 21:01
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Zhang
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Quote:
Originally Posted by bigfootedrockmidget View Post
Hi, do you have the mesh available?
What do you mean with aircraft inlet? You mean the inlet of the engine?
I appreciate your understanding. I would like to clarify that my model represents the engine inlet. I apologize for any confusion caused by my previous expression. I have uploaded the mesh file to Google Drive, and I hope it is accessible for your review. Please be aware that the file format is CGNS, exported using Tecplot, and it may be relatively large. Your assistance is greatly appreciated.

You can access the mesh file through the link provided below.
https://drive.google.com/file/d/11d2...ew?usp=sharing

Yours,
Zhang
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