Selected equations can be disabled globally using an Expert Parameter, however there is no option to disable the solving of equations on a per domain basis. If the intention is fix a variable value (e.g. velocity), a source term can be added to its equation. This will not result in solution speedup, however. For example, the following momentum source can be used to achieve a velocity [uspec,vspec,wspec] within a given subdomain : MOMENTUM SOURCE: Momentum Source X Component = -C*(u-uspec) Momentum Source Y Component = -C*(v-vspec) Momentum Source Z Component = -C*(w-wspec) Momentum Source Coefficient = -C END A similar approach can be used for other solution equations, such as AV’s. The idea behind this approach is that we create a source term with a very large, negative source coefficient. This allows it to dominate the equation and force the value of the dependent variable to the specified value.