87 research outputs found
Hybrid Riemann Solvers for Large Systems of Conservation Laws
In this paper we present a new family of approximate Riemann solvers for the
numerical approximation of solutions of hyperbolic conservation laws. They are
approximate, also referred to as incomplete, in the sense that the solvers
avoid computing the characteristic decomposition of the flux Jacobian. Instead,
they require only an estimate of the globally fastest wave speeds in both
directions. Thus, this family of solvers is particularly efficient for large
systems of conservation laws, i.e. with many different propagation speeds, and
when no explicit expression for the eigensystem is available. Even though only
fastest wave speeds are needed as input values, the new family of Riemann
solvers reproduces all waves with less dissipation than HLL, which has the same
prerequisites, requiring only one additional flux evaluation.Comment: 9 page
GMUSTA method for numerical simulation of dam break flow on mobile bed
River hydrodynamicsUnsteady open channel flow and dam brea
Time evolution of the anisotropies of the hydrodynamically expanding sQGP
In high energy heavy ion collisions of RHIC and LHC, a strongly interacting
quark gluon plasma (sQGP) is created. This medium undergoes a hydrodynamic
evolution, before it freezes out to form a hadronic matter. The initial state
of the sQGP is determined by the initial distribution of the participating
nucleons and their interactions. Due to the finite number of nucleons, the
initial distribution fluctuates on an event-by-event basis. The transverse
plane anisotropy of the initial state can be translated into a series of
anisotropy coefficients or eccentricities: second, third, fourth-order
anisotropy etc. These anisotropies then evolve in time, and result in
measurable momentum-space anisotropies, to be measured with respect to their
respective symmetry planes. In this paper we investigate the time evolution of
the anisotropies. With a numerical hydrodynamic code, we analyze how the speed
of sound and viscosity influence this evolution.Comment: 10 pages, 6 figures. To appear in the Gribov-85 Memorial Workshop's
proceedings volume. Supported by OTKA NK 10143
Applications of the DFLU flux to systems of conservation laws
The DFLU numerical flux was introduced in order to solve hyperbolic scalar
conservation laws with a flux function discontinuous in space. We show how this
flux can be used to solve systems of conservation laws. The obtained numerical
flux is very close to a Godunov flux. As an example we consider a system
modeling polymer flooding in oil reservoir engineering
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