form (const space V, const space& T, "2D");
Assembly the form associated to the rate of deformation tensor, i.e. the symmetric part of the gradient of a vector field. These derivative are usefull in fluid mechanic and elasticity.
/ | b(u,tau) = | 2 D(u) : tau dx, | / Omegawhere
2 D(u) = grad u + (grad u)^T
If the V space is a vector-valued P1 (resp. P2) finite element space, the T space may be a tensor-valued P0 (resp. P1d) one.
The following piece of code build the Laplacian form associated to the P1 approximation:
geo omega ("square"); space V (omega, "P1", "vector"); space T (omega, "P0", "tensor"); form b (V, T, "2D");