61 Dune::FieldVector<Scalar, 2> shearStress(0.0);
63 const Scalar artificialWaterDepth = this->
limitRoughH(roughnessHeight_, volVars.waterDepth());
65 const Scalar c = pow(volVars.waterDepth() + artificialWaterDepth, 1.0/6.0) * 1.0/(manningN_);
66 const Scalar uv = hypot(volVars.velocity(0), volVars.velocity(1));
67 const Scalar dimensionlessFactor = gravity_/(c*c);
69 shearStress[0] = dimensionlessFactor * volVars.velocity(0) * uv * volVars.density();
70 shearStress[1] = dimensionlessFactor * volVars.velocity(1) * uv * volVars.density();