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mfem/miniapps/navier/navier_mms.cpp
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2020-04-07 15:11:54 -07:00

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C++

// Copyright (c) 2010-2020, Lawrence Livermore National Security, LLC. Produced
// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
// LICENSE and NOTICE for details. LLNL-CODE-806117.
//
// This file is part of the MFEM library. For more information and source code
// availability visit https://mfem.org.
//
// MFEM is free software; you can redistribute it and/or modify it under the
// terms of the BSD-3 license. We welcome feedback and contributions, see file
// CONTRIBUTING.md for details.
//
// Navier MMS example
//
// A manufactured solution is defined as
//
// u = [pi * sin(t) * sin(pi * x)^2 * sin(2 * pi * y),
// -(pi * sin(t) * sin(2 * pi * x)) * sin(pi * y)^2].
//
// p = cos(pi * x) * sin(t) * sin(pi * y)
//
// The solution is used to compute the symbolic forcing term (right hand side),
// of the equation. Then the numerical solution is computed and compared to the
// exact manufactured solution to determine the error.
#include "navier_solver.hpp"
#include <fstream>
using namespace mfem;
using namespace navier;
struct s_NavierContext
{
int ser_ref_levels = 1;
int order = 5;
double kinvis = 1.0;
double t_final = 10 * 0.25e-4;
double dt = 0.25e-4;
bool pa = true;
bool ni = false;
bool visualization = false;
bool checkres = false;
} ctx;
void vel(const Vector &x, double t, Vector &u)
{
double xi = x(0);
double yi = x(1);
u(0) = M_PI * sin(t) * pow(sin(M_PI * xi), 2.0) * sin(2.0 * M_PI * yi);
u(1) = -(M_PI * sin(t) * sin(2.0 * M_PI * xi) * pow(sin(M_PI * yi), 2.0));
}
double p(const Vector &x, double t)
{
double xi = x(0);
double yi = x(1);
return cos(M_PI * xi) * sin(t) * sin(M_PI * yi);
}
void accel(const Vector &x, double t, Vector &u)
{
double xi = x(0);
double yi = x(1);
u(0) = M_PI * sin(t) * sin(M_PI * xi) * sin(M_PI * yi)
* (-1.0
+ 2.0 * pow(M_PI, 2.0) * sin(t) * sin(M_PI * xi)
* sin(2.0 * M_PI * xi) * sin(M_PI * yi))
+ M_PI
* (2.0 * ctx.kinvis * pow(M_PI, 2.0)
* (1.0 - 2.0 * cos(2.0 * M_PI * xi)) * sin(t)
+ cos(t) * pow(sin(M_PI * xi), 2.0))
* sin(2.0 * M_PI * yi);
u(1) = M_PI * cos(M_PI * yi) * sin(t)
* (cos(M_PI * xi)
+ 2.0 * ctx.kinvis * pow(M_PI, 2.0) * cos(M_PI * yi)
* sin(2.0 * M_PI * xi))
- M_PI * (cos(t) + 6.0 * ctx.kinvis * pow(M_PI, 2.0) * sin(t))
* sin(2.0 * M_PI * xi) * pow(sin(M_PI * yi), 2.0)
+ 4.0 * pow(M_PI, 3.0) * cos(M_PI * yi) * pow(sin(t), 2.0)
* pow(sin(M_PI * xi), 2.0) * pow(sin(M_PI * yi), 3.0);
}
int main(int argc, char *argv[])
{
MPI_Session mpi(argc, argv);
OptionsParser args(argc, argv);
args.AddOption(&ctx.ser_ref_levels,
"-rs",
"--refine-serial",
"Number of times to refine the mesh uniformly in serial.");
args.AddOption(&ctx.order,
"-o",
"--order",
"Order (degree) of the finite elements.");
args.AddOption(&ctx.dt, "-dt", "--time-step", "Time step.");
args.AddOption(&ctx.t_final, "-tf", "--final-time", "Final time.");
args.AddOption(&ctx.pa,
"-pa",
"--enable-pa",
"-no-pa",
"--disable-pa",
"Enable partial assembly.");
args.AddOption(&ctx.ni,
"-ni",
"--enable-ni",
"-no-ni",
"--disable-ni",
"Enable numerical integration rules.");
args.AddOption(&ctx.visualization,
"-vis",
"--visualization",
"-no-vis",
"--no-visualization",
"Enable or disable GLVis visualization.");
args.AddOption(
&ctx.checkres,
"-cr",
"--checkresult",
"-no-cr",
"--no-checkresult",
"Enable or disable checking of the result. Returns -1 on failure.");
args.Parse();
if (!args.Good())
{
if (mpi.Root())
{
args.PrintUsage(mfem::out);
}
return 1;
}
if (mpi.Root())
{
args.PrintOptions(mfem::out);
}
Mesh *mesh = new Mesh("../../data/inline-quad.mesh");
mesh->EnsureNodes();
GridFunction *nodes = mesh->GetNodes();
*nodes *= 2.0;
*nodes -= 1.0;
for (int i = 0; i < ctx.ser_ref_levels; ++i)
{
mesh->UniformRefinement();
}
if (mpi.Root())
{
std::cout << "Number of elements: " << mesh->GetNE() << std::endl;
}
ParMesh *pmesh = new ParMesh(MPI_COMM_WORLD, *mesh);
delete mesh;
// Create the flow solver.
NavierSolver naviersolver(pmesh, ctx.order, ctx.kinvis);
naviersolver.EnablePA(ctx.pa);
naviersolver.EnableNI(ctx.ni);
// Set the initial condition.
ParGridFunction *u_ic = naviersolver.GetCurrentVelocity();
VectorFunctionCoefficient u_excoeff(pmesh->Dimension(), vel);
u_ic->ProjectCoefficient(u_excoeff);
FunctionCoefficient p_excoeff(p);
// Add Dirichlet boundary conditions to velocity space restricted to
// selected attributes on the mesh.
Array<int> attr(pmesh->bdr_attributes.Max());
attr = 1;
naviersolver.AddVelDirichletBC(vel, attr);
Array<int> domain_attr(pmesh->attributes.Max());
domain_attr = 1;
naviersolver.AddAccelTerm(accel, domain_attr);
double t = 0.0;
double dt = ctx.dt;
double t_final = ctx.t_final;
bool last_step = false;
naviersolver.Setup(dt);
double err_u = 0.0;
double err_p = 0.0;
ParGridFunction *u_gf = nullptr;
ParGridFunction *p_gf = nullptr;
u_gf = naviersolver.GetCurrentVelocity();
p_gf = naviersolver.GetCurrentPressure();
for (int step = 0; !last_step; ++step)
{
if (t + dt >= t_final - dt / 2)
{
last_step = true;
}
naviersolver.Step(t, dt, step);
// Compare against exact solution of velocity and pressure.
u_excoeff.SetTime(t);
p_excoeff.SetTime(t);
err_u = u_gf->ComputeL2Error(u_excoeff);
err_p = p_gf->ComputeL2Error(p_excoeff);
if (mpi.Root())
{
printf("%11s %11s %11s %11s\n", "Time", "dt", "err_u", "err_p");
printf("%.5E %.5E %.5E %.5E err\n", t, dt, err_u, err_p);
fflush(stdout);
}
}
if (ctx.visualization)
{
char vishost[] = "localhost";
int visport = 19916;
socketstream sol_sock(vishost, visport);
sol_sock << "parallel " << mpi.WorldSize() << " " << mpi.WorldRank()
<< "\n";
sol_sock << "solution\n" << *pmesh << *u_ic << std::flush;
}
naviersolver.PrintTimingData();
// Test if the result for the test run is as expected.
if (ctx.checkres)
{
double tol = 1e-3;
if (err_u > tol || err_p > tol)
{
if (mpi.Root())
{
mfem::out << "Result has a larger error than expected."
<< std::endl;
}
return -1;
}
}
delete pmesh;
return 0;
}