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title: About Goma
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<h1>About Goma</h1>

<p>For a more comprehensive introduction look at the <a href="/files/goma_capabilities_august_2020.pdf">Goma Capabilities document (PDF, August 2020)</a></p>

<h3>What Does Goma 6.0 Do?</h3>
<p>Goma 6.0 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</p>
<h3>How Does Goma 6.0 Work?</h3>
<p>Goma 6.0 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</p>
<p>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.</p>
<p>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 6.0
also includes purely Eulerian boundary tracking methods on stationary meshes,
using either the level set or the overset-grid methods.</p>
<h3>Capabilities</h3>
<p>Goma's capability is based on customer need</p>

<ol>
<li><p>Mechanics — Includes all major branches of mechanics and more. Conjugate capability.</p></li>
<li><p>Material models and constitutive equations — Includes generalized Newtonian and VE 
for fluids, elastic and elastoviscoplastic for solids, Fickian, multicomponent, and 
non-Fickian fluxes, and more</p></li>
<li><p>Free surface and free boundary tracking — Solidification surfaces, capillary free 
surfaces, consolidation fronts, mold filling fronts, saturation fronts, user prescribed 
kinematics and geometry, ablation fronts, and more</p></li>
<li><p>Multidimensional with 2.5D capability. Full shell capability.</p></li>
<li><p>Platform generality — High-end, high-performance, and commodity hardware</p></li>
<li><p>User prescribed and user defined capability</p></li>
<li><p>Fluid-structural interactions — Computational Lagrangian solids and ale in both 
solids and fluids with Eulerian-Eulerian methods an active research area</p></li>
<li><p>Saturated and unsaturated, deformable, porous media — Poro-elastic and poro-plastic</p></li>
<li><p>Full-Newton coupled algorithms and automated continuation, augmenting conditions, 
stability analysis — All in a production setting</p></li>
<li><p>Other advanced features — Shell reduced order models, solid-model-based geometry 
support; advanced post processing features</p></li>
<li><p>Pixel and Voxel-to-mesh capability</p></li>
</ol>

<h2>Features and Highlights</h2>

<h3>Material Models - Fluids</h3>

<ul>
  <li>
    <p>Generalized Newtonian (concentration, temperature and shear-rate dependence). Carreau, Carreau-WLF, Molten glass, epoxy, epoxy cure, bingham-plastic</p>
    <p>Industry applications: Extrusion, polymer processing, coating</p>
  </li>
  <li>
    <p>Supension balance models (Phillips model for particle concentration, Krieger for viscosity)</p>
    <p>Industry applications: Multiphase manufacturing flows</p>
  </li>
  <li>
    <p>Single or multimode viscoelastic with EVSS split stress approach</p>
    <p>Industry applications: Extrusion, polymer processing, coating</p>
  </li>
</ul>

<h3>Thermo-physical Property and Phase Change Models</h3>

<ul>
  <li>
    <p>
      Vapor/liquid equilibrium - Ideal and Flory Huggins
    </p>
  </li>
  <li>
    <p>
      Discontinous variables approach for interphase mass-momentum transport (Schunk and Rao, IJNMF 1994)
    </p>
  </li>
  <li>
    <p>
      Vapor-pressur VS (T, C, K) models, Viz. Kelvin equation, Riedel, Antoine, etc.
    </p>
  </li>
  <li>
    <p>
      Liquid and solid equilibrium - Scheil or solute dependent solidification (latent heat release with enthalpy or intefacial Stephan condition).
    </p>
  </li>
  <li>
    <p>
      Liquid andSolid macrosegregation with Flemings-Mehrabian model
    </p>
  </li>
  <li>
    <p>
      Polymer thermoset and condensation curing
    </p>
  </li>
</ul>
<h3>Shell Elements</h3>
<ul>
  <li>
    <p>
      Shell Element Technology can be easily integrated into a large-aspect-ratio structure (shell elements can be membranes, inextensible shell, lubrication, or porous)  
    </p>
  </li>
  <li>
    <p>
      Goma 6.0 has integrated true curvilinear shell capability for lubrication (the first of its kind to our knowledge with continuum codes), porous, penetration, and integrated structure
    </p>
  </li>
</ul>
<h3>Mechanics and Algorithms</h3>
<ul>
  <li>
    <p>
      Comprehensive mechanics couplings allow the algorithms to run with minimal tuning  
    </p>
  </li>
  <li>
    <p>
      Advanced, automated machinery allows for complex algorithms (augmenting condition capability, linear stability, and high-order continuation) 
    </p>
  </li>
   <li>
    <p>
      Advanced, automated machinery allows for complex algorithms (augmenting condition capability, linear stability, and high-order continuation) and faster quadratic convergence
    </p>
  </li>
</ul>

<h3>Advanced Analysis Capabilities</h3>
<ul>
  <li>
    <p>
      Augmenting conditions (volume, mesh constrains, optimization) allows extreme analysis precision    
    </p>
  </li>
  <li>
    <p>
      ARPACK and Eggroll provide linear stability analysis in both 2D and 3D dynamic systems
    </p>
  </li>
</ul>