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M. Gerritsma

Publications and source records attributed to M. Gerritsma.

3 recordsLinked to original sources

Use of algebraic dual representations in domain decomposition methods for Darcy flow in 3D domain

In this work we use algebraic dual representations in conjunction with domain decomposition methods for Darcy equations. We define the broken Sobolev spaces and their finite dimensional counterparts. In addition, a global trace space is defined that connects the solution between the broken spaces. Use of dual representations results in a sparse metric free representation of the constraint on divergence of velocity, the pressure gradient term and on the continuity constraint across the sub domains. To demonstrate this, we solve two test cases: i) manufactured solution case, and ii) industrial benchmark reservoir modelling problem SPE10. The results demonstrate that the domain decomposition scheme, although with more unknowns, requires less memory and simulation time as compared to the continuous Galerkin formulation.

math.NA

Estimation and numerical validation of inf-sup constant for bilinear form (p, div u)

We give a derivation for the value of inf-sup constant for the bilinear form (p, div u). We prove that the value of inf-sup constant is equal to 1.0 in all cases and is independent of the size and shape of the domain. Numerical tests for validation of inf-sup constants is performed using finite dimensional spaces defined in \cite{2020jain} on two test domains i) a square of size $Ω= [0,1]^2$, ii) a square of size $Ω= [0,2]^2$, for varying mesh sizes and polynomial degrees. The numeric values are in agreement with the theoretical value of inf-sup term.

math.NA

A Higher Order Equilibrium Finite Element Method

In this paper a mixed spectral element formulation is presented for planar, linear elasticity. The degrees of freedom for the stress are integrated traction components, i.e. surface force components. As a result the tractions between elements are continuous. The formulation is based on minimization of the complementary energy subject to the constraints that the stress field should satisfy equilibrium of forces and moments. The Lagrange multiplier which enforces equilibrium of forces is the displacement field and the Lagrange multiplier which enforces equilibrium of moments is the rotation. The formulation satisfies equilibrium of forces pointwise if the body forces are piecewise polynomial. Equilibrium of moments is weakly satisfied. Results of the method are given on orthogonal and curvilinear domains and an example with a point singularity is given.

math.NA