In this paper we discuss recent applications of the Smoothed Particle Hydrodynamics (SPH) method to the simulation of supersonic turbulence in the interstellar medium, as well as giving an update on recent algorithmic developments in solving the equations of magnetohydrodynamics (MHD) in SPH. Using high resolution calculations (up to 134 million particles), we find excellent agreement with grid...

In this paper we describe an adaptive softening length formalism for collisionless N−body and self-gravitating Smoothed Particle Hydrodynamics (SPH) calculations which conserves momentum and energy exactly. This means that spatially variable softening lengths can be used in N−body calculations without secular increases in energy. The formalism requires the calculation of a small additional term...

We model regular and irregular design waves of interest in coastal ocean engineering, using a Numerical Wave Flume (NWF) based on Moving Particle Semi-Implicit (MPS) method. A key feature the is implementation new scheme for artificial viscosity, which original to Smoothed Hydrodynamics (SPH) method here formalised into MPS context. In addition, we complement NWF with wave generator dynamic bou...

The development of a methodology for the simulation of structure forming processes is highly desirable. The smoothed particle hydrodynamics (SPH) approach provides a respective framework for modeling the self-structuring of complex geometries. In this paper, we describe a diffusion-controlled phase separation process based on the Cahn-Hilliard approach using the SPH method. As a novelty for SPH...

We present a practical guide to Smoothed Particle Hydro-dynamics (SPH) and its application to astrophysical problems. Although remarkably robust, SPH must be used with care if the results are to be meaningful since the accuracy of SPH is sensitive to the arrangement of the particles and the form of the smoothing kernel. In particular, the initial conditions for any SPH simulation must consist o...

In this paper we show how a Lagrangian variational principle can be used to derive the Smoothed Particle Magnetohydrodynamics (SPMHD) equations for ideal Magnetohydrodynamics (MHD). We also consider the effect of a variable smoothing length in the Smoothed Particle Hydrodynamics (SPH) kernels, after which we demonstrate by numerical tests that the consistent treatment of terms relating to the g...

A new Chemo – Dynamical Smoothed Particle Hydrodynamic (CD – SPH) code is presented. The disk galaxy is described as a multi – fragmented gas and star system, embedded into the cold dark matter halo. The star formation (SF) process, SNII, SNIa and PN events as well as chemical enrichment of gas have been considered within the framework of standard SPH model. Using this model we try to describe ...

We describe a simple method for simulating the dynamics of small grains in a dusty gas, relevant to micron-sized grains in the interstellar medium and grains of centimetre size and smaller in protoplanetary discs. The method involves solving one extra diffusion equation for the dust fraction in addition to the usual equations of hydrodynamics. This “diffusion approximation for dust” is valid wh...

In this paper we report on the results of a joint eeort of astrophysicists and computer scientists to develop and implement a parallel program that enables us to solve large systems of hydrodynamic equations and covers a wide range of applications in astrophysics. We introduce the Distributed Threads System (DTS) as an environment for the development of portable parallel applications. The numer...

We review recent progress in understanding the hydrodynamics of compact binary mergers using relativistic smoothed particle hydrodynamics (SPH) codes. Recent results are discussed for both double neutron stars and black hole – neutron star binaries. The gravitational wave signals from these mergers contain a lot of information about the masses and radii of the stars and the equation of state of...