Nektar++
RCROutflow.cpp
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1///////////////////////////////////////////////////////////////////////////////
2//
3// File: RCROutflow.cpp
4//
5// For more information, please see: http://www.nektar.info
6//
7// The MIT License
8//
9// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
10// Department of Aeronautics, Imperial College London (UK), and Scientific
11// Computing and Imaging Institute, University of Utah (USA).
12//
13// License for the specific language governing rights and limitations under
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31//
32// Description:
33//
34///////////////////////////////////////////////////////////////////////////////
35
38
39namespace Nektar
40{
41
42std::string RCROutflow::className =
44 "RCR-terminal", RCROutflow::create, "RCR outflow boundary condition");
45
49 : PulseWaveBoundary(pVessel, pSession, pressureArea)
50{
51 m_session->LoadParameter("TimeStep", m_timestep);
52}
53
55 const Array<OneD, const Array<OneD, NekDouble>> &inarray,
59 [[maybe_unused]] const NekDouble time, int omega, int offset, int n)
60{
61 NekDouble A_r = 0.0;
62 NekDouble u_r = 0.0;
63 NekDouble A_u = 0.0;
64 NekDouble u_u = 0.0;
65 NekDouble A_l = 0.0;
66 NekDouble u_l = 0.0;
67 NekDouble c_0 = 0.0;
68 NekDouble R1 = 0.0;
69 NekDouble R2 = 0.0;
70 NekDouble POut = m_pout;
71 NekDouble rho = m_rho;
72
74
75 // Pointers to the domains
76 vessel[0] = m_vessels[2 * omega];
77 vessel[1] = m_vessels[2 * omega + 1];
78
79 /* Find the terminal RCR boundary condition and calculates
80 the updated velocity and area as well as the updated
81 boundary conditions */
82
83 /* Load terminal resistance, capacitance, outflow pressure,
84 and number of points from the input file */
85 NekDouble RT = ((vessel[0]->GetBndCondExpansions())[n])->GetCoeffs()[0];
86 NekDouble C = ((vessel[1]->GetBndCondExpansions())[n])->GetCoeffs()[0];
87 int nq = vessel[0]->GetTotPoints();
88
89 // Get the values of all variables needed for the Riemann problem
90 A_l = inarray[0][offset + nq - 1];
91 u_l = inarray[1][offset + nq - 1];
92
93 // Goes through the first resistance; calculates c_0
94 m_pressureArea->GetC(c_0, beta[omega][nq - 1], A_0[omega][nq - 1],
95 A_0[omega][nq - 1], alpha[omega][nq - 1]);
96
97 /* Calculate R1 and R2, R1 being calculated so as
98 to eliminate reflections in the vessel */
99 R1 = rho * c_0 / A_0[omega][nq - 1];
100
101 if (R1 > 0.9 * RT)
102 {
103 // In case the resistance is lower than the characteristic impedance.
104 R1 = 0.9 * RT;
105 }
106
107 R2 = RT - R1;
108
109 // Call the R RiemannSolver
110 R_RiemannSolver(R1, A_l, u_l, A_0[omega][nq - 1], beta[omega][nq - 1],
111 alpha[omega][nq - 1], m_pc, A_u, u_u);
112
113 /* Fix the boundary conditions in the virtual region to ensure
114 upwind state matches the boundary condition at the next time step */
115 A_r = A_l;
116 u_r = 2 * u_u - u_l;
117
118 /* Goes through the CR system, which
119 just updates the pressure pc */
120 m_pc += (m_timestep / C) * (A_u * u_u - (m_pc - POut) / R2);
121
122 // Store the updated values
123 (vessel[0]->UpdateBndCondExpansion(n))->UpdatePhys()[0] = A_r;
124 (vessel[1]->UpdateBndCondExpansion(n))->UpdatePhys()[0] = u_r;
125}
126
128 NekDouble A_0, NekDouble beta, NekDouble alpha,
129 NekDouble POut, NekDouble &A_u, NekDouble &u_u)
130{
131 NekDouble W1 = 0.0;
132 NekDouble c = 0.0;
133 NekDouble cL = 0.0;
134 NekDouble I = 0.0;
135 NekDouble A_calc = 0.0;
136 NekDouble FA = 0.0;
137 NekDouble dFdA = 0.0;
138 NekDouble delta_A_calc = 0.0;
139 NekDouble P = 0.0;
140 NekDouble rho = m_rho;
141
142 int proceed = 1;
143 int iter = 0;
144 int MAX_ITER = 100;
145
146 // Tolerances for the algorithm
147 NekDouble Tol = 1.0E-10;
148
149 // Calculate the wave speed
150 m_pressureArea->GetC(cL, beta, A_l, A_0, alpha);
151
152 // Riemann invariant \f$W_1(Al,ul)\f$
153 m_pressureArea->GetW1(W1, u_l, beta, A_l, A_0, alpha);
154
155 // Newton Iteration (Area only)
156 A_calc = A_l;
157 while ((proceed) && (iter < MAX_ITER))
158 {
159 iter += 1;
160
161 m_pressureArea->GetPressure(P, beta, A_calc, A_0, 0, 0, alpha);
162 m_pressureArea->GetC(c, beta, A_calc, A_0, alpha);
163 m_pressureArea->GetCharIntegral(I, beta, A_calc, A_0, alpha);
164
165 FA = R * A_calc * (W1 - I) - P + POut;
166 dFdA = R * (W1 - I - c) - c * c * rho / A_calc;
167 delta_A_calc = FA / dFdA;
168 A_calc -= delta_A_calc;
169
170 if (sqrt(delta_A_calc * delta_A_calc) < Tol)
171 {
172 proceed = 0;
173 }
174 }
175
176 m_pressureArea->GetPressure(P, beta, A_calc, A_0, 0, 0, alpha);
177
178 // Obtain u_u and A_u
179 u_u = (P - POut) / (R * A_calc);
180 A_u = A_calc;
181}
182
183} // namespace Nektar
tKey RegisterCreatorFunction(tKey idKey, CreatorFunction classCreator, std::string pDesc="")
Register a class with the factory.
Array< OneD, MultiRegions::ExpListSharedPtr > m_vessels
PulseWavePressureAreaSharedPtr m_pressureArea
LibUtilities::SessionReaderSharedPtr m_session
void R_RiemannSolver(NekDouble R, NekDouble A_l, NekDouble u_l, NekDouble A_0, NekDouble beta, NekDouble alpha, NekDouble POut, NekDouble &A_u, NekDouble &u_u)
Definition: RCROutflow.cpp:127
NekDouble m_pc
Definition: RCROutflow.h:72
static std::string className
Definition: RCROutflow.h:68
void v_DoBoundary(const Array< OneD, const Array< OneD, NekDouble > > &inarray, Array< OneD, Array< OneD, NekDouble > > &A_0, Array< OneD, Array< OneD, NekDouble > > &beta, Array< OneD, Array< OneD, NekDouble > > &alpha, const NekDouble time, int omega, int offset, int n) override
Definition: RCROutflow.cpp:54
RCROutflow(Array< OneD, MultiRegions::ExpListSharedPtr > pVessel, const LibUtilities::SessionReaderSharedPtr pSession, PulseWavePressureAreaSharedPtr pressureArea)
Definition: RCROutflow.cpp:46
NekDouble m_timestep
Definition: RCROutflow.h:71
static PulseWaveBoundarySharedPtr create(Array< OneD, MultiRegions::ExpListSharedPtr > &pVessel, const LibUtilities::SessionReaderSharedPtr &pSession, PulseWavePressureAreaSharedPtr &pressureArea)
Definition: RCROutflow.h:58
std::shared_ptr< SessionReader > SessionReaderSharedPtr
@ beta
Gauss Radau pinned at x=-1,.
Definition: PointsType.h:59
@ P
Monomial polynomials .
Definition: BasisType.h:62
std::shared_ptr< PulseWavePressureArea > PulseWavePressureAreaSharedPtr
BoundaryFactory & GetBoundaryFactory()
double NekDouble
scalarT< T > sqrt(scalarT< T > in)
Definition: scalar.hpp:285