void set_lid_driven_bcs(TransientLinearImplicitSystem & system)
{
unsigned short int
u_var = system.variable_number("vel_x"),
v_var = system.variable_number("vel_y");
// This problem *does* require a pressure pin, there are Dirichlet
// boundary conditions for u and v on the entire boundary.
system.get_equation_systems().parameters.set<bool>("pin_pressure") = true;
// Get a convenient reference to the System's DofMap
DofMap & dof_map = system.get_dof_map();
{
// u=v=0 on bottom, left, right
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(0);
boundary_ids.insert(1);
boundary_ids.insert(3);
std::vector<unsigned int> variables;
variables.push_back(u_var);
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
{
// u=1 on top
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(u_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ConstFunction<Number>(1.)));
}
{
// v=0 on top
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
}
void set_poiseuille_bcs(TransientLinearImplicitSystem & system)
{
unsigned short int
u_var = system.variable_number("vel_x"),
v_var = system.variable_number("vel_y");
// This problem does not require a pressure pin, the Neumann outlet
// BCs are sufficient to set the value of the pressure.
system.get_equation_systems().parameters.set<bool>("pin_pressure") = false;
// Get a convenient reference to the System's DofMap
DofMap & dof_map = system.get_dof_map();
{
// u=v=0 on top, bottom
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(0);
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(u_var);
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
{
// u=quadratic on left
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(3);
std::vector<unsigned int> variables;
variables.push_back(u_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ParsedFunction<Number>("4*y*(1-y)")));
}
{
// v=0 on left
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(3);
std::vector<unsigned int> variables;
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
}
void set_lid_driven_bcs(TransientLinearImplicitSystem & system)
{
unsigned short int
u_var = system.variable_number("vel_x"),
v_var = system.variable_number("vel_y");
// Get a convenient reference to the System's DofMap
DofMap & dof_map = system.get_dof_map();
{
// u=v=0 on bottom, left, right
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(0);
boundary_ids.insert(1);
boundary_ids.insert(3);
std::vector<unsigned int> variables;
variables.push_back(u_var);
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
{
// u=1 on top
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(u_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ConstFunction<Number>(1.)));
}
{
// v=0 on top
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
}
void set_stagnation_bcs(TransientLinearImplicitSystem & system)
{
unsigned short int
u_var = system.variable_number("vel_x"),
v_var = system.variable_number("vel_y");
// This problem does not require a pressure pin, the Neumann outlet
// BCs are sufficient to set the value of the pressure.
system.get_equation_systems().parameters.set<bool>("pin_pressure") = false;
// Get a convenient reference to the System's DofMap
DofMap & dof_map = system.get_dof_map();
{
// u=v=0 on bottom
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(0);
std::vector<unsigned int> variables;
variables.push_back(u_var);
variables.push_back(v_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
{
// u=0 on left (symmetry)
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(3);
std::vector<unsigned int> variables;
variables.push_back(u_var);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ZeroFunction<Number>()));
}
{
// u = k*x on top
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(u_var);
// Set up ParsedFunction parameters
std::vector<std::string> additional_vars;
additional_vars.push_back("k");
std::vector<Number> initial_vals;
initial_vals.push_back(1.);
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ParsedFunction<Number>("k*x",
&additional_vars,
&initial_vals)));
}
{
// v = -k*y on top
std::set<boundary_id_type> boundary_ids;
boundary_ids.insert(2);
std::vector<unsigned int> variables;
variables.push_back(v_var);
// Set up ParsedFunction parameters
std::vector<std::string> additional_vars;
additional_vars.push_back("k");
std::vector<Number> initial_vals;
initial_vals.push_back(1.);
// Note: we have to specify LOCAL_VARIABLE_ORDER here, since we're
// using a ParsedFunction to set the value of v_var, which is
// actually the second variable in the system.
dof_map.add_dirichlet_boundary(DirichletBoundary(boundary_ids,
variables,
ParsedFunction<Number>("-k*y",
&additional_vars,
&initial_vals),
LOCAL_VARIABLE_ORDER));
}
}
