CFD Online Discussion Forums - Turbulent NACA 64-A010 stability response problem

https://drive.google.com/drive/folde...Wb?usp=sharing

Dear all,
I have a problem with my simulation: I would like to simulate the aeroelastic response of a NACA64A010 airfoil in viscous turbulent transonic flow (Ma=0.8, flutter speed index=1.5)
Here you can find my configuration file
Code:


% ------------- DIRECT, ADJOINT, AND LINEARIZED PROBLEM DEFINITION ------------%

%

% Physical governing equations (EULER, NAVIER_STOKES,

%                               WAVE_EQUATION, HEAT_EQUATION, FEM_ELASTICITY,

%                               POISSON_EQUATION)

SOLVER= RANS

%

% Specify turbulent model (NONE, SA, SA_NEG, SST)

KIND_TURB_MODEL= SA

%

% Mathematical problem (DIRECT, CONTINUOUS_ADJOINT)

MATH_PROBLEM= DIRECT

%

% Write binary restart files (YES, NO)

WRT_BINARY_RESTART= NO

%

% Read binary restart files (YES, NO)

READ_BINARY_RESTART= NO

%

%

% -------------------- COMPRESSIBLE FREE-STREAM DEFINITION --------------------%

%

% Flow non-dimensionalization (DIMENSIONAL, FREESTREAM_PRESS_EQ_ONE,

%                              FREESTREAM_VEL_EQ_MACH, FREESTREAM_VEL_EQ_ONE)

REF_DIMENSIONALIZATION= DIMENSIONAL

%

% Mach number (non-dimensional, based on the free-stream values)

MACH_NUMBER= 0.8

%

% Angle of attack (degrees, only for compressible flows)

AOA= 0.0

%

% Free-stream option to choose between density and temperature (default) for

% initializing the solution (TEMPERATURE_FS, DENSITY_FS)

INIT_OPTION=TD_CONDITIONS

FREESTREAM_OPTION= TEMPERATURE_FS

%

% Free-stream temperature (288.15 K by default)

FREESTREAM_TEMPERATURE= 1312.188

FREESTREAM_PRESSURE=315850.322

REYNOLDS_NUMBER=10000000

REYNOLDS_LENGTH=1.0

%

% ---- IDEAL GAS, POLYTROPIC, VAN DER WAALS AND PENG ROBINSON CONSTANTS -------%

%

% Different gas model (STANDARD_AIR, IDEAL_GAS, VW_GAS, PR_GAS)

FLUID_MODEL= IDEAL_GAS

%

% --------------------------- VISCOSITY MODEL ---------------------------------%

%

% Viscosity model (SUTHERLAND, CONSTANT_VISCOSITY).

VISCOSITY_MODEL= SUTHERLAND

%

% --------------------------- THERMAL CONDUCTIVITY MODEL ----------------------%

%

% Conductivity model (CONSTANT_CONDUCTIVITY, CONSTANT_PRANDTL).

CONDUCTIVITY_MODEL= CONSTANT_PRANDTL

%

% 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



% ---------------------- REFERENCE VALUE DEFINITION ---------------------------%

%

% Reference origin for moment computation (m or in)

REF_ORIGIN_MOMENT_X = -0.5

REF_ORIGIN_MOMENT_Y = 0.00

REF_ORIGIN_MOMENT_Z = 0.00

%

% Reference length for pitching, rolling, and yawing non-dimensional

% moment (m or in)

REF_LENGTH= 1.0

%

% Reference area for force coefficients (0 implies automatic

% calculation) (m^2 or in^2)

REF_AREA= 1.0

%



% ------------------------- UNSTEADY SIMULATION -------------------------------%

%

% Time domain

TIME_DOMAIN=YES

%

% Unsteady simulation (NO, TIME_STEPPING, DUAL_TIME_STEPPING-1ST_ORDER, 

%                      DUAL_TIME_STEPPING-2ND_ORDER, SPECTRAL_METHOD)

TIME_MARCHING= DUAL_TIME_STEPPING-2ND_ORDER

%

% Time Step for dual time stepping simulations (s)

TIME_STEP= 0.00174532925199 

% 

% 36 steps per period, based on the pitch natural frequency

%

% Total Physical Time for dual time stepping simulations (s)

MAX_TIME= 100.0

%

% Number of internal iterations (dual time method)

INNER_ITER= 110



% ----------------------- DYNAMIC MESH DEFINITION -----------------------------%

SURFACE_MOVEMENT= AEROELASTIC

%

% Motion mach number (non-dimensional). Used for initializing a viscous flow

% with the Reynolds number and for computing force coeffs. with dynamic meshes.

MACH_MOTION= 0.8

%

% Moving wall boundary marker(s) (NONE = no marker, ignored for RIGID_MOTION)

MARKER_MOVING= ( airfoil )



% -------------- AEROELASTIC SIMULATION (Typical Section Model) ---------------%

% Activated by GRID_MOVEMENT_KIND option

%

% The flutter speed index (modifies the freestream condition in the solver)

FLUTTER_SPEED_INDEX = 1.5

%

% Natural frequency of the spring in the plunging direction (rad/s)

PLUNGE_NATURAL_FREQUENCY = 100

%

% Natural frequency of the spring in the pitching direction (rad/s)

PITCH_NATURAL_FREQUENCY = 100

%

% The airfoil mass ratio

AIRFOIL_MASS_RATIO = 60

%

% Distance in semichords by which the center of gravity lies behind

% the elastic axis

CG_LOCATION = 1.8

%

% The radius of gyration squared (expressed in semichords)

% of the typical section about the elastic axis

RADIUS_GYRATION_SQUARED = 3.48

%

% Solve the aeroelastic equations every given number of internal iterations

AEROELASTIC_ITER = 3



% --------------------------- GUST SIMULATION ---------------------------------%

%

% Apply a wind gust (NO, YES)

WIND_GUST = YES

%

% Type of gust (NONE, TOP_HAT, SINE, ONE_M_COSINE, VORTEX, EOG)

GUST_TYPE = TOP_HAT

%

% Direction of the gust (X_DIR or Y_DIR)

GUST_DIR = Y_DIR

%

% Gust wavelenght (meters)

GUST_WAVELENGTH= 7.90876841815

% 1/4 of period based on the pitch natural frequency

%

% Number of gust periods

GUST_PERIODS= 1.0

%

% Gust amplitude (m/s)

GUST_AMPL= 10.242

% Corresponds to 1 deg AoA.

%

% Time at which to begin the gust (sec)

GUST_BEGIN_TIME= 0.0

%

% Location at which the gust begins (meters) */

GUST_BEGIN_LOC= -7.90876841815



% -------------------- BOUNDARY CONDITION DEFINITION --------------------------%

%

% old was Euler wall boundary marker(s) (NONE = no marker)

% old was MARKER_EULER= ( airfoil )

%

% Navier-Stokes wall boundary marker(s) (NONE = no marker)

MARKER_HEATFLUX= ( airfoil, 0.0)

%

% Far-field boundary marker(s) (NONE = no marker)

MARKER_FAR= ( farfield )



% ------------------------ 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 )



% ------------- COMMON PARAMETERS DEFINING THE NUMERICAL METHOD ---------------%

%

% Numerical method for spatial gradients (GREEN_GAUSS, WEIGHTED_LEAST_SQUARES)

NUM_METHOD_GRAD= GREEN_GAUSS 

%

% CFL number (stating value for the adaptive CFL number)

CFL_NUMBER= 4.0



% ------------------------ LINEAR SOLVER DEFINITION ---------------------------%

%

% Linear solver or smoother for implicit formulations (BCGSTAB, FGMRES, SMOOTHER)

LINEAR_SOLVER= FGMRES

%

% Preconditioner of the Krylov linear solver (ILU, LU_SGS, LINELET, JACOBI)

LINEAR_SOLVER_PREC= LU_SGS

%

% Minimum error of the linear solver for implicit formulations

LINEAR_SOLVER_ERROR= 1E-4

%

% Max number of iterations of the linear solver for the implicit formulation

LINEAR_SOLVER_ITER= 5



% -------------------------- MULTIGRID PARAMETERS -----------------------------%

%

% Multi-grid levels (0 = no multi-grid)

MGLEVEL= 3

%

% 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= 0.75

%

% Damping factor for the correction prolongation

MG_DAMP_PROLONGATION= 0.75



% -------------------- FLOW NUMERICAL METHOD DEFINITION -----------------------%

%

% Convective numerical method (JST, LAX-FRIEDRICH, CUSP, ROE, AUSM, HLLC,

%                              TURKEL_PREC, MSW)

CONV_NUM_METHOD_FLOW= JST

%

% Spatial numerical order integration (1ST_ORDER, 2ND_ORDER, 2ND_ORDER_LIMITER)

MUSCL_FLOW= YES

%

% Slope limiter (VENKATAKRISHNAN, BARTH_JESPERSEN)

SLOPE_LIMITER_FLOW= VENKATAKRISHNAN

%

% Entropy fix coefficient (0.0 implies no entropy fixing, 1.0 implies scalar

%                          artificial dissipation)

ENTROPY_FIX_COEFF= 0.001

%

% 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



% -------------------- TURBULENT NUMERICAL METHOD DEFINITION ------------------%

%

% Convective numerical method (SCALAR_UPWIND)

CONV_NUM_METHOD_TURB= SCALAR_UPWIND

%

% Spatial numerical order integration (1ST_ORDER, 2ND_ORDER, 2ND_ORDER_LIMITER)

%

MUSCL_TURB= NO

%

% Time discretization (EULER_IMPLICIT)

TIME_DISCRE_TURB= EULER_IMPLICIT



% ------------------------ GRID DEFORMATION PARAMETERS ------------------------%

%

% Linear solver or smoother for implicit formulations (FGMRES, RESTARTED_FGMRES, BCGSTAB)

DEFORM_LINEAR_SOLVER= FGMRES

%

% Preconditioner of the Krylov linear solver (ILU, LU_SGS, JACOBI)

DEFORM_LINEAR_SOLVER_PREC= LU_SGS

%

% Number of smoothing iterations for mesh deformation

DEFORM_LINEAR_SOLVER_ITER= 500

%

% Number of nonlinear deformation iterations (surface deformation increments)

DEFORM_NONLINEAR_ITER= 1

%

% Print the residuals during mesh deformation to the console (YES, NO)

DEFORM_CONSOLE_OUTPUT= NO

%

% Minimum residual criteria for the linear solver convergence of grid deformation

DEFORM_LINEAR_SOLVER_ERROR= 1E-14

%

% Type of element stiffness imposed for FEA mesh deformation (INVERSE_VOLUME, 

%                                          WALL_DISTANCE, CONSTANT_STIFFNESS)

DEFORM_STIFFNESS_TYPE= INVERSE_VOLUME

%

% Visualize the surface deformation (NO, YES)

VISUALIZE_SURFACE_DEF= NO

%

% Visualize the volume deformation (NO, YES)

VISUALIZE_VOLUME_DEF= NO



% --------------------------- CONVERGENCE PARAMETERS --------------------------%

%

% Number of total iterations

TIME_ITER= 720

%

% Convergence criteria (CAUCHY, RESIDUAL)

%

CONV_CRITERIA= RESIDUAL

%

% Field to apply Cauchy Criterion to

CONV_FIELD= REL_RMS_DENSITY

%

% Min value of the residual (log10 of the residual)

CONV_RESIDUAL_MINVAL= -8

%

% Start convergence criteria at iteration number

CONV_STARTITER= 0

%

% Number of elements to apply the criteria

CONV_CAUCHY_ELEMS= 100

%

% Epsilon to control the series convergence

CONV_CAUCHY_EPS= 1E-10

%



% ------------------------- INPUT/OUTPUT INFORMATION --------------------------%

%

% Mesh input file

MESH_FILENAME= NACA64A010v6.su2

%

% Mesh input file format (SU2, CGNS)

MESH_FORMAT= SU2

%

% Restart flow input file

SOLUTION_FILENAME= solution_flow.dat

%

% Output file format (TECPLOT, TECPLOT_BINARY, PARAVIEW,

%                     FIELDVIEW, FIELDVIEW_BINARY)

TABULAR_FORMAT= CSV

%

% Output file convergence history (w/o extension) 

CONV_FILENAME= history

%

% Output file restart flow

RESTART_FILENAME= restart_flow.dat

%

% Output file flow (w/o extension) variables

VOLUME_FILENAME= flow

%

% Output file surface flow coefficient (w/o extension)

SURFACE_FILENAME= surface_flow

%

% Writing solution file frequency

WRT_SOL_FREQ= 1000

%

OUTPUT_FILES= (RESTART,CSV,SURFACE_CSV,SURFACE_PARAVIEW,PARAVIEW)

% Writing solution file frequency for physical time steps (dual time)

WRT_SOL_FREQ_DUALTIME= 1000

%

% Writing convergence history frequency

WRT_CON_FREQ= 1

%

% Writing convergence history frequency (dual time, only written to screen)

WRT_CON_FREQ_DUALTIME= 1

%

% Screen output

SCREEN_OUTPUT= (TIME_ITER, INNER_ITER, RMS_DENSITY, RMS_ENERGY, LIFT, DRAG_ON_SURFACE, PLUNGE, PITCH) 

%

% history output

HISTORY_OUTPUT=(ITER, TIME_DOMAIN, REL_RMS_RES, RMS_RES, AERO_COEFF, TAVG_AERO_COEFF, CAUCHY,AEROELASTIC)
and I attach the files I am using. My problem is that -given Mach and flutter index- I should get an unstable aeroelastic response (i.e. the flutter should increase in amplitude), but instead I get always a stable response.

Could you please help me? I really tried to change everything, but the problem is always there.

Thank you in advance

Kevin