Tdyn reference manual
Materials are groups of physical properties and other data that identify a material, fluid or solid to be used in the analysis.
For any problem that needs definition of materials, there is a database of existing materials that can be assigned to entities. The user can also create new materials derived from the existing ones and assign them as well.
To create a new Material, press the New Material button in the Material window, write a new name and change some of its properties. By pressing Accept, a new Material is created taking an existing one as a base Material, which means that the new Material will have the same fields as the base one. All new values for the fields can be entered when defining the new material. It is also possible to redefine existing Materials by entering new values directly in the fields.
From Materials window, it is also possible to start the Tdyn Initial and Conditional Data window (see Initial and Conditional Data section for further information) and the Tdyn Modules Data window, by pressing the corresponding button (see Figure 7)
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Figure 7. Init (Tdyn
Initial and Conditional Data window) |
Remarks:
If a mesh has already been generated and new materials are assigned to the geometry or some of the existing ones are removed, it is necessary to mesh again.
In this section only the main Materials will be presented. Therefore, Materials with different names can be found in the Materials database. Anyhow, all these Materials will be based on (i.e. they will have the same properties fields) the ones shown here.
Fluid Materials are groups of physical properties and other data that can be assigned to surfaces (2D) or volumes (3D). This set of physical properties corresponds to a fluid to be analysed.
Density: Density of the fluid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the density may be defined in the menu next to the density entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Viscosity: Viscosity of the fluid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the viscosity may be defined in the menu next to the viscosity entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Compressibility: Compressibility factor of the fluid. Generally speaking, it is defined by the inverse of the square of the velocity of the sound in the fluid. Here it can be defined by a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the compressibility may be defined in the menu next to the this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Acceleration Field: External acceleration vector acting on fluid. May be defined by constants or functions. See Function Syntax section for further information.
Remarks:
It is recommended to insert functions with a smoothed start up for this additional acceleration. Otherwise it can create oscillations in the solution.
Vertical field will be added to the vertical component of the gravity, as an additional acceleration.
Density: Density of the fluid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the density may be defined in the menu next to the density entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Remarks:
Density entry in this window is the same for RANSOL and HEATRANS data. Once is changed in one module will be automatically updated in the other.
Specific Heat: Specific heat (CP) of the fluid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information. Units of the specific heat may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Thermal Conductivity: Thermal conductivity (k) of the fluid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information. Units of the thermal conductivity may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Floatability: Floatability effect – Boussinesq type - (due to small changes of density) of a fluid. May be a constant or a function. See Function Syntax section for further information. This property controls the bouyancy effect due to the variations of temperature in the fluid. Standard effects are modelled by inserting the function β·(T-T0) where β is the volume expansion of the fluid and T0 is the temperature of reference. In this case, buoyancy effect will be taken into account by a variation of density of the fluid proportional to the temperature (r = ro· β·(T-T0)). This term is undimensional.
Heat Source Field: Volumetric heat source in the fluid. May be a constant or a function. See Function Syntax section for further information. Units of the heat source field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Heat Reaction Field: Volumetric heat reaction in the fluid. This entry will be added as a reactive term in the system of equations (i.e. a source term depending linearly to the temperature). May be a constant or a function. See Function Syntax section for further information. Units of the heat reaction field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
ADVECT label of Fluid Material window (see Figure 8) is splitted in three frames. Upper frame shows the standard equation that is solved for every species. Right lower frame shows the entries of the coefficients of the differential equation of the selected species. Finally, left lower frame shows a list of the defined species and the currently selected species. To select a different species, just click on its name. New species can be created / deleted by pressing the +/- buttons.
Remarks:
Any change in the names or creation / deletion of species will affect all existing fluid materials.
Figure 8. Fluid Material window. ADVECT label |
Options available in ADVECT label of the Fluid Material window are shown next:
f1: Advection factor of the selected species (see Figure 8). This property may be defined by a constant or a function. See Function Syntax section for further information. Advection factor is undimensional.
f2: Total diffusion of the selected species (see Figure 8). Please note that this value must include the turbulent and physical diffusion of species. This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the total diffusion field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f3: Reactive term of the selected species (see Figure 8). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the reactive field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f4: Source of concentration of the selected species (see Figure 8).This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the source of concentration field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f5: Decantation effect in the selected species. This property controls the decantation effect or relative movement of species respectively to the fluid in the advection process. This process happens due to the action of a gravity force on variations of a concentration of species in this fluid. It must be a constant property of this species in this fluid. Tdyn takes this effect into account by means of an additional velocity, proportional to the concentration of the species and the gravity.
Decantation effect is only produced in the OY direction in Tdyn2D or in the OZ direction in Tdyn3D. Note that this effect must be very small in order to preserve the stability of the algorithm.
Units of the decantation field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Remarks:
Decantation effect is not fully operative in the current version of Tdyn. However, it can be simulated by inserting a source of the species including a term proportional to the concentration gradient.
URSOLVER label of Fluid Material window (see Figure 9) is splitted in three frames. Upper frame shows the standard equation that is solved for every variable. Right lower frame shows the entries of the coefficients of the differential equation of the selected variable. Finally, left lower frame shows a list of the defined variable and the currently selected variable. To select a different variable, just click on its name. New variablescan be created / deleted by pressing the +/- button.
Remarks:
Any change in the names or creation / deletion of variables will affect all existing fluid materials.
Options available in URSOLVER of the Fluid Material window are shown next:
f1t: Temporal factor of the selected variable (see Figure 9). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the temporal factor field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Figure 9. Fluid Material window. URSOLVER label |
f1c: Advection factor of the selected variable (see Figure 9). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the advection factor field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f2: Total diffusion of the selected variable (see Figure 9). Please note that this value must include the turbulent and physical diffusion of variable. This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the total diffusion field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f3: Reactive term of the selected variable (see Figure 9). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the reactive field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f4: Source of the selected variable (see Figure 9).This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the source field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Solid Materials are groups of physical properties and other data, that can be assigned to surfaces (2D) or a volumes (3D). This set of physical properties corresponds to a solid to be analysed.
Fluid Density: Density of the fluid moving in the porous media (solid). It may be a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the density may be defined in the menu next to the density entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Fluid Viscosity: Viscosity of the fluid moving in the porous media (solid). It may be a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the viscosity may be defined in the menu next to the viscosity entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Acceleration Field: External acceleration vector acting on the fluid moving in the porous media (solid). It may be defined by constants or functions. See Function Syntax section for further information.
Remarks:
It is recommended to insert functions with a smoothed start up for this additional acceleration. Otherwise it can create oscillations in the solution.
Vertical field will be added to the vertical component of the gravity, as an additional acceleration.
Density: Density of the solid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information.
Units of the density may be defined in the menu next to the density entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Specific Heat: Specific heat (CP) of the solid. It may be a constant or a function (always greater than zero). See Function Syntax section for further information. Units of the specific heat may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Thermal Conductivity Matrix: Thermal conductivity (k) matrix of the solid. The matrix must be defined in Cartesian coordinates by constants or function (always greater than zero). See Function Syntax section for further information. Units of the thermal conduction may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Remarks:
If only one value of the thermal conductivity is available, it should be inserted in the diagonal terms of the matrix.
Floatability: Floatability effect – Boussinesq type – (due to small changes of density) of the solid. May be a constant or a function. See Function Syntax section for further information. This property controls the bouyancy effect due to the variations of temperature in the fluid moving in the porous solid. Standard effects are modelled by inserting the function β·(T-T0) where β is the volume expansion of the fluid and T0 is the temperature of reference. In this case, buoyancy effect will be taken into account by a variation of density of the fluid proportional to the temperature (r = ro· β·(T-T0)). This term is undimensional.
Heat Source Field: Volumetric heat source in the solid. It may be a constant or a function. See Function Syntax section for further information. Units of the heat source field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Heat Reaction Field: Volumetric heat reaction in the solid. This entry will be added as a reactive term in the system of equations (i.e. a source term depending linearly to the temperature). It may be a constant or a function. See Function Syntax section for further information. Units of the heat reaction field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
ADVECT label of Solid Material window (see Figure 10) is splitted in three frames. Upper frame shows the standard equation that is solved for every species. Right lower frame shows the entries of the coefficients of the differential equation of the selected species. Finally, left lower frame shows a list of the defined species and the currently selected species. To select a different species, just click on its name. New species can be created / deleted by pressing the +/- button.
Remarks:
Any change in the names or creation / deletion of species will affect all existing solid materials.
Figure 10. Solid Material window. ADVECT label |
Options available in ADVECT label of the Solid Material window are shown next:
f1: Advection factor of the selected species (see Figure 10). This property may be defined by a constant or a function. See Function Syntax section for further information. Advection factor is undimensional.
f2: Total diffusion matrix of the selected species (see Figure 10). Please note that these values must include the turbulent and physical diffusion of species. This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the total diffusion field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Remarks:
If only one value of the diffusion of the species is available, it should be inserted in the diagonal terms of the matrix.
f3: Reactive term of the selected species (see Figure 10). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the reactive field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f4: Source of concentration of the selected species (see Figure 10).This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the source of concentration field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
URSOLVER label of Solid Material window (see Figure 11) is splitted in three frames. Upper frame shows the standard equation that is solved for every variable. Right lower frame shows the entries of the coefficients of the differential equation of the selected variable. Finally, left lower frame shows a list of the defined variable and the currently selected variable. To select a different variable, just click on its name. New variablescan be created / deleted by pressing the +/- button.
Remarks:
Any change in the names or creation / deletion of variables will affect all existing solid materials.
Options available in URSOLVER of the Solid Material window are shown next:
f1t: Temporal factor of the selected variable (see Figure 11). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the temporal factor field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f1c: Advection factor of the selected variable (see Figure 11). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the advection factor field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Figure 11. Solid Material window. URSOLVER label |
f2: Total diffusion matrix of the selected variable (see Figure 11). Please note that this value must include the turbulent and physical diffusion of variable. This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the total diffusion field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Remarks:
If only one value of the diffusion of the variable is available, it should be inserted in the diagonal terms of the matrix.
f3: Reactive term of the selected variable (see Figure 11). This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the reactive field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
f4: Source of the selected variable (see Figure 11).This property may be defined by a constant or a function. See Function Syntax section for further information. Units of the source field may be defined in the menu next to this entry. It is possible to define additional units by entering new dimensionally correct units in the box (see Units Syntax section for further information).
Options available in RAMSOLID of the Solid Material window are shown next. These options are only available in Tdyn3D.
E (Young modulus): Young modulus of the solid (2.1·1011 N/m2 for steel). See RamSeries Reference Manual for further information. Units of the Young modulus may be defined in the menu next to this entry.
ν (Poisson coefficient): Poisson coefficient of the solid (0.3 for steel). See RamSeries Reference Manual for further information. Poisson coefficient is undimensional.
Specific weight: The Specific weight is the self-weight of the solid (different from density). The weight is considered in the direction of the gravity. See RamSeries Reference Manual for further information. Its units are defined based on Young modulus units (see above).
εo (Mechanical Strain): Initial (for the current time step) strain of the solid. This strain is passed to the structural analysis solver to calculate the corresponding stresses. This option can be used to define a thermal expansion effect given by α·(Tm-To), being To the (initial) reference temperature. See RAMSOLID coupling information in the Tdyn Modules data window for further information. Mechanical strain is undimensional.