[tonino]

Hi guys, I created a mesh within pointwise and am trying to do the simulations on a convergent-divergent nozzle considering the model of dissociation N2. When I do the simulation I get the following error:

----------------------------- Begin Solver -----------------------------
Segmentation fault (core dumped)

The boundary condition it is:

i=1: Subsonic inlet, pt = 100 atm, Tt = 5600 K (stagnation conditions)
i=IMAX: Free stream
j=1: Symmetry conditions
j=JMAX: Inviscid wall.

The configuration file it is:


COMPRESSIBLE FREE-STREAM DEFINITION

Mach number (non-dimensional, based on the free-stream values)
MACH_NUMBER= 23.9
%
% Angle of attack (degrees, only for compressible flows)
AoA= 0.0
%
% Side-slip angle (degrees, only for compressible flows)
SIDESLIP_ANGLE= 0.0
%
% Free-stream pressure (101325.0 N/m^2 by default)
FREESTREAM_PRESSURE= 19.7594
%
% Free-stream temperature (288.15 K by default)
FREESTREAM_TEMPERATURE= 254.0
%
% Free-stream vibrational-electronic temperature (288.15 K by default)
FREESTREAM_TEMPERATURE_VE= 254.0
%
% Reynolds number (non-dimensional, based on the free-stream values)
REYNOLDS_NUMBER= 19500
%
% Reynolds length (1 m by default)
REYNOLDS_LENGTH= 1.0

% ---------------------- 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_MOMENT= 1.0
%
% Reference area for force coefficients (0 implies automatic calculation)
REF_AREA= 1.0

% -------------------- BOUNDARY CONDITION DEFINITION --------------------------%
%
% Euler wall boundary marker(s) (NONE = no marker)
MARKER_EULER= ( Inviscid_wall )

MARKER_INLET= ( Inlet, 300, 19956.1, 1.0, 0.0, 0.0 )
%
% Far-field boundary marker(s) (NONE = no marker)
MARKER_FAR= ( Inflow, Outflow, Top )
%
% Symmetry boundary marker(s) (NONE = no marker)
MARKER_SYM= ( Symmetry )

MARKER_OUTLET= ( Outlet, 101300 )

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

% ------------- COMMON PARAMETERS DEFINING THE NUMERICAL METHOD ---------------%
%
% Numerical method for spatial gradients (GREEN_GAUSS, WEIGHTED_LEAST_SQUARES)
NUM_METHOD_GRAD= WEIGHTED_LEAST_SQUARES
%
% Courant-Friedrichs-Lewy condition of the finest grid
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, 1.0, 100.0 )
%
% Runge-Kutta alpha coefficients
RK_ALPHA_COEFF= ( 0.66667, 0.66667, 1.000000 )
%
% Number of total iterations
EXT_ITER= 3000

% ------------------------ LINEAR SOLVER DEFINITION ---------------------------%
%
% Linear solver for the implicit (or discrete adjoint) formulation (LU_SGS,
% SYM_GAUSS_SEIDEL, BCGSTAB, GMRES)
LINEAR_SOLVER= FGMRES
%
% Linear solver preconditioner
LINEAR_SOLVER_PREC= LU_SGS
%
% Min error of the linear solver for the implicit formulation
LINEAR_SOLVER_ERROR= 1E-8
%
% Max number of iterations of the linear solver for the implicit formulation
LINEAR_SOLVER_ITER= 10

% -------------------------- MULTIGRID PARAMETERS -----------------------------%
%
% Multi-grid Levels (0 = no multi-grid)
MGLEVEL= 0
%
% Multi-grid cycle (V_CYCLE, W_CYCLE, FULLMG_CYCLE)
MGCYCLE= V_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= 0.85
%
% Damping factor for the correction prolongation
MG_DAMP_PROLONGATION= 0.85

% -------------------- FLOW NUMERICAL METHOD DEFINITION -----------------------%
%
% Convective numerical method (JST, LAX-FRIEDRICH, CUSP, ROE, AUSM, HLLC,
% TURKEL_PREC, MSW)
CONV_NUM_METHOD_FLOW= AUSM
%
% Spatial numerical order integration (1ST_ORDER, 2ND_ORDER, 2ND_ORDER_LIMITER)
%
SPATIAL_ORDER_FLOW= 2ND_ORDER
%
% Slope limiter (VENKATAKRISHNAN, MINMOD)
SLOPE_LIMITER_FLOW= VENKATAKRISHNAN
%
% Coefficient for the limiter
LIMITER_COEFF= 0.3
%
% 1st, 2nd and 4th order artificial dissipation coefficients
AD_COEFF_FLOW= ( 0.15, 0.5, 0.02 )
%
% Time discretization (RUNGE-KUTTA_EXPLICIT, EULER_IMPLICIT, EULER_EXPLICIT)
TIME_DISCRE_FLOW= EULER_IMPLICIT

% -------------------- TNE2 NUMERICAL METHOD DEFINITION -----------------------%
%
% Convective numerical method (ROE, AUSM, HLLC)
CONV_NUM_METHOD_TNE2= AUSM
%
% Spatial numerical order integration (1ST_ORDER, 2ND_ORDER, 2ND_ORDER_LIMITER)
%
SPATIAL_ORDER_TNE2= 1ST_ORDER
%
% Slope limiter (VENKATAKRISHNAN)
SLOPE_LIMITER_TNE2= VENKATAKRISHNAN
%
% Time discretization (RUNGE-KUTTA_EXPLICIT, EULER_IMPLICIT, EULER_EXPLICIT)
TIME_DISCRE_TNE2= EULER_IMPLICIT

% ----------------------- GEOMETRY EVALUATION PARAMETERS ----------------------%
%
% Geometrical evaluation mode (ANALYSIS, GRADIENT)
GEO_MODE= GRADIENT

% --------------------------- CONVERGENCE PARAMETERS --------------------------%
%
% Convergence criteria (CAUCHY, RESIDUAL)
%
CONV_CRITERIA= RESIDUAL
%
% Residual reduction (order of magnitude with respect to the initial value)
RESIDUAL_REDUCTION= 5
%
% Min value of the residual (log10 of the residual)
RESIDUAL_MINVAL= -8
%
% Start convergence criteria at iteration number
STARTCONV_ITER= 10
%
% Number of elements to apply the criteria
CAUCHY_ELEMS= 100
%
% Epsilon to control the series convergence
CAUCHY_EPS= 1E-10
%
% Function to apply the criteria (LIFT, DRAG, NEARFIELD_PRESS, SENS_GEOMETRY,
% SENS_MACH, DELTA_LIFT, DELTA_DRAG)
CAUCHY_FUNC_FLOW= DRAG
CAUCHY_FUNC_ADJFLOW= SENS_GEOMETRY

the mesh it is:



I would be grateful for any help you could provide.

Thanks.

[talbring]

Hi tonino,

the most important part is missing: what about the math problem options (probably just a copy & paste thing).


Then you reference some boundary markers that are not existent in your mesh I guess (Wall, Inflow, Outflow, Top). So remove the option MARKER_FAR and set MARKER_{PLOTTING, MONITORING, DESIGNING) to ( Inviscid_Wall ).

Maybe this already helps.

[amitavamandal]

In regard to the above mentioned problem, I have the following queries.
1. Reynold no, corresponding to which condition?
2. Which is the ideal boundary condition for this case i.e. supersonic or pressure boundary?
Regards
Amitava Mandal