Tdyn reference manual
Modules data refers to all the specific information needed to use a particular Tdyn module. See Introduction section for more information about Tdyn modules.
Tdyn Modules Data window can be started from Data > Modules Data.
Velocity Advect Stabilisation: Order of the FIC advection stabilisation term in the Navier Stokes equations. Three available options are Auto, 4th_Order and 2nd_Order.
Remarks:
The 4th order term increases the accuracy of the solution and is recommended in most of the cases. However in some problems it may cause instabilities.
Auto mode will automatically switch between 4th and 2nd order scheme, depending on the smoothness of the solution.
Velocity Control Level: Level of control of unstabilities (0 means Off). If unstabilities are found in the velocity field when using the 2nd_Order Velocity Advect Stabilisation, first try to reduce Time Increment, then to increase this value. Note that high values may cause over-diffusive results.
Velocity Inner Iterations: Number of iterations of the inner nonlinear fluid flow momentum eq. solver (performed every external iteration).
Velocity Norm: Velocity Euclidean norm used to check convergence in the non-linear iteration loop.
Pressure Stabilisation: Scheme to be used in the stabilisation of the Pressure solver of the Navier Stokes equations.
Pressure Inner Iterations: Number of iterations of the inner nonlinear navier stokes pressure solver (performed every external iteration).
Pressure Norm: Pressure Euclidean norm used to check convergence in the non-linear iteration loop.
Gravity Vector: The gravity vector have to be inserted here. The corresponding units have to be inserted in the right box.
Turbulence Model: Select the turbulence model to be used in the solution of the fluid flow problem.
Laminar: Navier Stokes equations are solved (i.e. Reynolds stress tensor is neglected and therefore only direct simulation of turbulence is done).
Mixing_Length: Basic turbulence model based in the Prandtl [[6]] hypothesis, where the turbulence length scale (L) is given in the ELen Field field.
Smagorinsky: Basic large eddy simulation (LES) turbulence model based on the description done in [[7]]. The implementation includes an eddy viscosity damping in the boundary layer area. See Turbulence modelling section for further information.
Kinetic_Energy: One equation k model for turbulent flows with integration to the wall, where the turbulence length scale (L) is given in the ELen Field field.
K_Energy_Two_Layers: One equation k model for turbulent flows with integration to the wall, where the turbulence length scale (L) is given in the ELen Field field. The implementation of this model includes an eddy viscosity damping in the boundary layer area.
K_E_High_Reynolds: Two-equation k-ε model for turbulent flows. The model implemented is based on the standard formulation with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
K_E_Two_Layers: Two-equation k-ε model for turbulent flows with integration to the wall. This implementation uses the high-Re k-ε model only away from the wall in the fully turbulent region, and the near-wall viscosity affected layer is resolved with a one-equation model involving a length-scale prescription. See Turbulence modelling section for further information.
K_E_Lam_Bremhorst: Two-equation k-ε model for turbulent flows with integration to the wall. The model implemented is based on the description done in [[8]] with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
K_E_Launder_Sharma: Two-equation k-ε model for turbulent flows with integration to the wall. The model implemented is based on the description done by Launder and Sharma [[9]] with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
K_Omega: Two equation k-ω model for turbulent flows with integration to the wall. The model implemented is based on the description done by Wilcox [[10]] with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
K_Omega_SST: Two-equation model for turbulent flows with integration to the wall, expressed in terms of a k-ω model formulation. The k-ω SST shear-stress-transport model combines several desirable elements of standard k-ε and k-ω models. The implementation is based on the description done in [11] with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
K_KT: Two-equation k-kτ model for turbulent flows with integration to the wall. The model implemented is based on the description done by Wilcox [10] with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
Spalart_Allmaras: One equation model for turbulent flows with integration to the wall. The implementation is based on the description of the model done in [[11]] with some modifications to be used with different wall boundary conditions. See Turbulence modelling section for further information.
Turbulence Advect Stabilisation: Order of the FIC advection stabilisation term in the turbulence equations. Three available options are Auto, 4th_Order and 2nd_Order.
Remarks:
The 4th order term increases the accuracy of the solution and is recommended in most of the cases. However in some problems it may cause instabilities.
Auto mode will automatically switch between 4th and 2nd order scheme, depending on the smoothness of the solution.
Turbulence Control Level: Level of control of unstabilities for turbulence (0 means Off). If unstabilities are found in the eddy viscosity field when using the 2nd_Order Turbulence Advect Stabilisation, first try to reduce Time Increment and refine the mesh when possible, then to increase this value. Note that high values may cause over-diffusive results.
Turbulence Inner Iterations: Number of iterations of the inner nonlinear turbulence solver (performed every external iteration).
Tvisco Min Ratio: Eddy viscosity ratio with the minimum of initial values of the eddy viscosity, used to calculate the minimum admissible value.
Fix Turbulence on Bodies: If Yes is selected, turbulence variables will have a fixed value, given by the selected law of the wall on the bodies surfaces. If No is selected, natural boundary condition will be applied.
Tvisco Max Ratio: Eddy viscosity ratio with the maximum of initial values of the eddy viscosity, used to calculate the maximum admissible value (> 1.0).
Kenergy Min Ratio: Eddy kinetic energy (k) ratio with maximum of the initial values of k, used to calculate the minimum admissible value.
Kenergy Max Ratio: Eddy kinetic energy (k) ratio with maximum of the initial values of k, used to calculate the maximum admissible value.
Epsilon Min Ratio: Epsilon (ε) ratio with the maximum of initial values of ε, used to calculate the minimum admissible value.
Epsilon Max Ratio: Epsilon (ε) ratio with the maximum of initial values of ε, used to calculate the maximum admissible value.
Omega Min Ratio: Omega (ω) ratio with the maximum of initial values of ω, used to calculate the minimum admissible value.
Omega Max Ratio: Omega (ω) ratio with the maximum of initial values of ω, used to calculate the maximum admissible value (> 1.0).
K Tau Min Ratio: K Tau (kτ) ratio with the maximum of initial values of kτ, used to calculate the minimum admissible value.
K Tau Max Ratio: K Tau (kτ) ratio with the maximum of initial values of kτ, used to calculate the maximum admissible value.
Turbulence_Control_Level: Level of turbulence stabilisation control (0 means Off). If unstabilities are found in the eddy viscosity field, refine the mesh when possible, reduce Time_Increment or increase this value. Note that too high values may cause over-diffusive eddy viscosity results. Recommended value is 2.
EddyKEnergy_Production_Limit: Maximum ratio between the Eddy kinetic energy production and reaction term. This limiter may prevent the unrealistic buildup of eddy viscosity in the stagnation region of the bodies. Recommended value is 20.0.
Epsilon_Production_Limit: Maximum ratio between the Epsilon production and reaction term.
Epsilon_Reaction_Limit: Maximum ratio between the Epsilon reaction and production term.
Omega_Production_Limit: Maximum ratio between the Omega production and reaction term.
Omega_Reaction_Limit: Maximum ratio between the Omega reaction and production term.
EddyViscoT_Production_Limit: Maximum ratio between the Spallart-Almarax model production and reaction term.
EddyViscoT_Reaction_Limit: Maximum ratio between the Spallart-Almarax model reaction and production term.
Temp. Advect Stabilisation: Order of the FIC advection stabilisation term in the temperature equation. Three available options are Auto, 4th_Order and 2nd_Order.
Remarks:
The 4th order term increases the accuracy of the solution and is recommended in most of the cases. However in some problems it may cause instabilities.
Auto mode will automatically switch between 4th and 2nd order scheme, depending on the smoothness of the solution.
Temp. Control Level: Level of control of unstabilities (0 means Off). If unstabilities are found in the velocity field when using the 2nd_Order Temp. Advect Stabilisation, first try to reduce Time Increment, then to increase this value. Note that high values may cause over-diffusive results.
Temp. Inner Iterations: Number of iterations of the inner (nonlinear) temperature eq. solver (performed every external iteration).
Temperature Norm: Temperature Euclidean norm used to check convergence in the non-linear iteration loop.
Options below have to be defined for every existing Species.
Max Limit: Maximum acceptable value of the species concentration.
Min Limit: Maximum acceptable value of the species concentration.
Convergence Norm: Euclidean norm of species concentration used to check convergence in the non-linear iteration loop.
Inner Iterations: Number of iterations of the inner (nonlinear) species concentration eq. solver (performed every external iteration).
Advect Stabilisation: Order of the FIC advection stabilisation term in the species concentration equation. Three available options are Auto, 4th_Order and 2nd_Order.
Remarks:
The 4th order term increases the accuracy of the solution and is recommended in most of the cases. However in some problems it may cause instabilities.
Auto mode will automatically switch between 4th and 2nd order scheme, depending on the smoothness of the solution.
Stability Control: Level of control of unstabilities (0 means Off). If unstabilities are found in the species concentration field when using the 2nd_Order Advect Stabilisation, first try to reduce Time Increment, then to increase this value. Note that high values may cause over-diffusive results.
Volume Conservation: If this box is selected, conservation of species concentration will be enforced.
Reference Units: Reference units for boundary conditions of the species concentration. Basic units of species concentration is a generic symbol 'C'.
Options below have to be defined for every existing Species.
Max Limit: Maximum acceptable value of the variable field.
Min Limit: Maximum acceptable value of the variable field.
Convergence Norm: Euclidean norm of variable field used to check convergence in the non-linear iteration loop.
Inner Iterations: Number of iterations of the inner (nonlinear) variable eq. solver (performed every external iteration).
Advect Stabilisation: Order of the FIC advection stabilisation term in the variable equation. Three available options are Auto, 4th_Order and 2nd_Order.
Remarks:
The 4th order term increases the accuracy of the solution and is recommended in most of the cases. However in some problems it may cause instabilities.
Auto mode will automatically switch between 4th and 2nd order scheme, depending on the smoothness of the solution.
Stability Control: Level of control of unstabilities (0 means Off). If unstabilities are found in the variable field when using the 2nd_Order Advect Stabilisation, first try to reduce Time Increment, then to increase this value. Note that high values may cause over-diffusive results.
Volume Conservation: If this box is selected, conservation of variable field will be enforced.
Reference Units: Reference units for boundary conditions of the variable. Basic units of variables is a generic symbol 'U'.
Wave Elevation Norm: Euclidean norm of wave elevation field used to check convergence in the non-linear iteration loop.
Fluid Mesh Deformation: Mesh updating in fluid domain may be done by three different procedures:
ByBodies: Mesh deformation only takes into account the movement of the defined bodies.
ByFunctions: Mesh deformation is performed following the values given in the Fluid Deformation Increment field.
ByAllData: Mesh deformation algorithm try to fulfil all the requirements (movement of bodies, deformation given in Fluid Deformation Increment field and boundary conditions).
Update fluid mesh every (steps): Mesh updating in fluid domain in carried out every Update fluid mesh every (steps) steps.
Fluid Deformation Increment: Functions defining fluid mesh deformation have to be inserted here. These functions must define the deformation increment for every time step.
Solid Mesh Deformation: Mesh updating in solid domain may be done by three different procedures:
ByBodies: Mesh deformation only takes into account the movement of the defined bodies.
ByFunctions: Mesh deformation is performed following the values given in the Solid Deformation Increment field.
ByAllData: Mesh deformation algorithm try to fulfil all the requirements (movement of bodies, deformation given in Solid Deformation Increment field and boundary conditions).
Update solid mesh every (steps): Mesh updating in solid domain in carried out every Update solid mesh every (steps) steps.
Solid Deformation Increment: Functions defining solid mesh deformation have to be inserted here. These functions must define the deformation increment for every time step.
Smooth results per material: When there are materials with different rigidity in one model, strengths are not continuous between materials. If this option is set, strengths will be displayed as discontinuous in the material boundaries. Note: When set, results mesh will have more nodes than preprocessing mesh.
Gravity Vector: The gravity vector may be inserted here. Note that this vector is the same inserted in the RANSOL page. If any entry is changed here, it will be automatically updated in the RANSOL page.
Coupling type: When structural analysis is coupled to any other problem (i.e. temperature) through Mechanical Strain field (see Solid Material section), the type of coupling have to be defined. Available options are:
None: Coupling effect is neglected.
Step by Step: Coupling effect is re-evaluated every time step.
Steady State: Coupling effect is evaluated only for the last time step.
Coupling every (steps): If Step by Step option is selected for Coupling type, it is possible to control if the re-evaluation of the coupling effect and therefore the structural analysis is made every time step of every Coupling every (steps) time steps.