About Goma

Goma is software for numerical simulation of multiphysics continuum processes, including moving geometry, phase-change, fluid-structural interactions, complex rheology, and chemical reactions. It solves the fundamental equations of mass, momentum, energy, and chemical species transport using the finite-element method.

Goma solves problems from all branches of mechanics, including fluid mechanics, solid mechanics, chemical reactions and mass transport, and energy transport. The conservation principles for momentum, mass, species, and energy, together with material constitutive relations, can be described by partial differential equations. The equations are made discrete for solution on a digital computer with the finite element method in space and the finite difference method in time. The resulting nonlinear, time-dependent, algebraic equations are solved with a full Newton-Raphson method. The linearized equations are solved with direct or Krylov-based iterative solvers. The simulations can be run on a single processor or on multiple processors in parallel using domain decomposition, which can greatly speed up engineering analysis.

Goma is designed as a general mechanics code, with no features that tie it to any particular application. Applications, or problems to be solved, are specified completely in input files, which include code and material properties specifications. The multitude of differential equations, material constitutive equations, and boundary conditions has evolved with the applications, but they are all from theories fully published in the open literature and Goma's theory manual.

Although many of Goma's applications involve fixed boundaries, Goma really stands out when applied to problems with dynamic geometries, i.e. free and moving boundaries. A novel algorithm for mesh motion is at the heart of Goma, where boundary motion is accommodated by allowing mesh nodes to move as if they were a pseudo-solid rubbery material. This is where Goma gets its name, which means "rubber elasticity" in Spanish. From the principles of kinematics, this algorithm can be applied to either fluid- or solid-material regions or to problems of fluid-structure interactions. The problem can be Lagrangian, meaning that the mesh moves with the material, or Arbitrary Lagrangian Eulerian, meaning that in some places the mesh moves with the material and in others it does not. Goma also includes purely Eulerian boundary tracking methods on stationary meshes, using either the level set or the overset-grid methods.