iterative.hpp File Reference

Iterative Riemann solver for GSPH (van Leer 1997). More...

#include "shambackends/math.hpp"
#include "shambackends/sycl.hpp"

Include dependency graph for iterative.hpp:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Classes
struct	shammodels::gsph::riemann::RiemannResult< Tscal >
	Result of Riemann solver. More...

Namespaces
namespace	shammodels
	namespace for models

Functions
template<class Tscal>
RiemannResult< Tscal >	shammodels::gsph::riemann::iterative_solver (Tscal u_L, Tscal rho_L, Tscal p_L, Tscal u_R, Tscal rho_R, Tscal p_R, Tscal gamma, Tscal tol=Tscal{1.0e-6}, u32 max_iter=20)
	Approximate ("two-shock") iterative Riemann solver (van Leer 1997).
template<class Tscal>
RiemannResult< Tscal >	shammodels::gsph::riemann::hllc_solver (Tscal u_L, Tscal rho_L, Tscal p_L, Tscal u_R, Tscal rho_R, Tscal p_R, Tscal gamma)
	HLL approximate Riemann solver.

Detailed Description

Iterative Riemann solver for GSPH (van Leer 1997).

Author

Guo Yansong (guo.y.nosp@m.anso.nosp@m.ng.ng.nosp@m.y@gm.nosp@m.ail.c.nosp@m.om)

Timothée David–Cléris (tim.s.nosp@m.hamr.nosp@m.ock@p.nosp@m.roto.nosp@m.n.me)

Yona Lapeyre (yona..nosp@m.lape.nosp@m.yre@e.nosp@m.ns-l.nosp@m.yon.f.nosp@m.r)

Implements an approximate ("two-shock") iterative Riemann solver for ideal gas: the same shock-relation impedance formula is used on both sides regardless of whether that side is physically a shock or a rarefaction, solved via Newton-Raphson to find (p*, v*). This is close to exact for shock-dominated pairs, but can be significantly inaccurate for strong rarefactions / near-vacuum conditions – see math/riemann/exact.hpp for the true exact solver (Toro-style, case-classified shock/rarefaction relations solved via bisection).

References:

• van Leer, B. (1997) "Towards the ultimate conservative difference scheme"
• Toro, E.F. (2009) "Riemann Solvers and Numerical Methods for Fluid Dynamics"

Definition in file iterative.hpp.

Function Documentation

hllc_solver()

template<class Tscal>

RiemannResult< Tscal > shammodels::gsph::riemann::hllc_solver ( Tscal u_L, Tscal rho_L, Tscal p_L, Tscal u_R, Tscal rho_R, Tscal p_R, Tscal gamma )

inline

HLL approximate Riemann solver.

Harten-Lax-van Leer approximate solver following the reference implementation. Uses Roe-averaged wave speeds for better wave speed estimates.

Template Parameters

Tscal

Scalar type (f32 or f64)

Parameters

u_L	Left state velocity
rho_L	Left state density
p_L	Left state pressure
u_R	Right state velocity
rho_R	Right state density
p_R	Right state pressure
gamma	Adiabatic index

Returns

RiemannResult with p_star and v_star

Definition at line 196 of file iterative.hpp.

iterative_solver()

template<class Tscal>

RiemannResult< Tscal > shammodels::gsph::riemann::iterative_solver ( Tscal u_L, Tscal rho_L, Tscal p_L, Tscal u_R, Tscal rho_R, Tscal p_R, Tscal gamma, Tscal tol = Tscal{1.0e-6}, u32 max_iter = 20 )

inline

Approximate ("two-shock") iterative Riemann solver (van Leer 1997).

Solves for an ideal gas using Newton-Raphson iteration on the shock relation applied to both sides. Returns the interface pressure and velocity (p*, v*). See math/riemann/exact.hpp for the true exact solver.

The left/right convention is:

• Left state (L): particle on the "minus" side of the interface
• Right state (R): particle on the "plus" side of the interface
• Positive velocity points from L to R

Template Parameters

Tscal

Scalar type (f32 or f64)

Parameters

u_L	Left state velocity (normal component)
rho_L	Left state density
p_L	Left state pressure
u_R	Right state velocity (normal component)
rho_R	Right state density
p_R	Right state pressure
gamma	Adiabatic index
tol	Convergence tolerance (default: 1e-6)
max_iter	Maximum iterations (default: 20)

Returns

RiemannResult with p_star and v_star

Definition at line 75 of file iterative.hpp.