Number of EQ#

Number of EQ = <integer>

Description / Usage#

This card is required for each material section in the Problem Description File. It specifies how many equations (i.e., equation cards, [EQ =]) follow for this material section, including the mesh motion equations if appropriate. This number of equations is only for the current material, since each material has its own equation section.

The single input parameter is defined as

The number of EQ cards following this card. Only the first Number of EQ equations are read; if there are more EQ cards than specified by <integer>, Goma ignores the extras. If <integer> is set to -1, Goma will automatically count the number of EQ cards between the Number of EQ card and the END OF EQ card.

Examples#

The following is a sample card that sets the number of equations to 5:

Number of EQ = 5

Technical Discussion#

For equation specification in Goma, it is important to remember that a scalar equation has a single equation entry (e.g. fill, species, voltage, shear rate, etc.), while a vector equation (e.g. momentum, mesh, mom_solid, etc.) has an entry for each component of the vector. Thus, if you were solving a two-dimension flow problem, you would need to specify both U1 and U2 components of the momentum equation explicitly. The same holds true for tensor equations (e.g. stress and velocity gradient); each term of the tensor is specified explicitly. The one exception to this rule is for multimode viscoelasticity where the first mode equations are specified through the equation card and then the auxiliary modes are set by the Number of viscoelastic modes card. Please see the viscoelastic tutorial memo (Rao, 2000) for a detailed discussion of multimode viscoelasticity.

References#

GT-014.1: Tutorial for Running Viscoelastic Flow Problems with GOMA, June 21, 2000, R. R. Rao

Equation Cards

Following the Number of EQ card, the equation cards, or records, are racked as intended up to the *END OF EQ card or to the number specified, with one equation record per line. Each card begins with the “EQ =” string, followed by the equation name, e.g., energy, some basis function and trial function information, and finally a series of term multipliers. These multipliers are intended to provide a means of activating or deactivating terms of an equation, and hence should be set to zero or one. However, one can use these multipliers as a way of adjusting the scaling of individual terms. Exercise caution in using these factors as expedients for transport coefficients; for instance the equation term multiplier for the momentum diffusion term affects both the isotropic stress term (pressure) and the deviatoric stress. It is recommended that you consult the example tutorial menus and problems to get a feel for the structure of this section. A sample input file structure including the EQ section is shown in the figure at the beginning of this chapter.