Search results for " Hydrodynamics"

Numerical Modelling of Room Thermal Comfort Conditions

2006

Particular heat transfer coefficients of building elements gives quantitative notion only about heat losses through this building element. Analysis of the overall heat balance and heat losses of complete building and study of particular contribution of building elements in overall balance allows one to figure out the state of the building and find the building elements of bounding construction with most significant heat losses. Project variants of the buildings (or rebuilding in case of renovation), which ensure the desirable economy of energy and proportions of investments can be find varying the proportions of the surface area of building elements (e.g., windows and doors). A lot of facto…

A shallow water SPH model with PML boundaries

2015

Abstract We focus on the study and implementation of Smoothed Particle Hydrodynamics (SPH) numerical code to deal with non-reflecting boundary conditions, starting from the Perfect Matched Layer (PML) approach. Basically, the method exploits the concept of a physical damping which acts on a fictitious layer added to the edges of computational domain. In this paper, we develop the study of time dependent shallow waves propagating on a finite 2D-XY plane domain and their behavior in the presence of circular and, more generic, rectangular boundary absorbing layers. In particular, an analysis of variation of the layer׳s thickness versus the absorbing efficiency is conducted. In our model, the m…

On the use of SPH for Mechanical Engineering structural analyses: an elastic linear case

2011

Stability of hydrodynamical relativistic planar jets

2004

The effects of relativistic dynamics and thermodynamics in the development of Kelvin-Helmholtz instabilities in planar, relativistic jets along the early phases (namely linear and saturation phases) of evolution has been studied by a combination of linear stability analysis and high-resolution numerical simulations for the most unstable first reflection modes in the temporal approach. Three different values of the jet Lorentz factor (5, 10 and 20) and a few different values of specific internal energy of the jet matter (from 0.08 to $60.0 c^2$) have been considered. Figures illustrating the evolution of the perturbations are also shown.

PANORMUS-SPH. A new Smoothed Particle Hydrodynamics solver for incompressible flows

2015

Abstract A new Smoothed Particle Hydrodynamics (SPH) solver is presented, fully integrated within the PANORMUS package [7] , originally developed as a Finite Volume Method (FVM) solver. The proposed model employs the fully Incompressible SPH approach, where a Fractional Step Method is used to make the numerical solution march in time. The main novelty of the proposed model is the use of a general and highly flexible procedure to account for different boundary conditions, based on the discretization of the boundary surfaces with a set of triangles and the introduction of mirror particles with suitable hydrodynamic properties. Both laminar and turbulent flows can be solved (the latter using t…

Meshless Electrophysiological Modeling of Cardiac Resynchronization Therapy—Benchmark Analysis with Finite-Element Methods in Experimental Data

2022

Computational models of cardiac electrophysiology are promising tools for reducing the rates of non-response patients suitable for cardiac resynchronization therapy (CRT) by optimizing electrode placement. The majority of computational models in the literature are mesh-based, primarily using the finite element method (FEM). The generation of patient-specific cardiac meshes has traditionally been a tedious task requiring manual intervention and hindering the modeling of a large number of cases. Meshless models can be a valid alternative due to their mesh quality independence. The organization of challenges such as the CRT-EPiggy19, providing unique experimental data as open access, enables b…

A simple procedure to improve the pressure evaluation in hydrodynamic context using the SPH

2009

In literature, it is well know that the Smoothed Particle Hydrodynamics method can be affected by numerical noise on the pressure field when dealing with liquids. This can be highly dangerous when an SPH code is dynamically coupled with a structural solver. In this work a simple procedure is proposed to improve the computation of the pressure distribution in the dynamics of liquids. Such a procedure is based on the use of a density diffusion term in the equation for the mass conservation. This diffusion is a pure numerical effect, similar to the well known artificial viscosity originally proposed in SPH method to smooth out the shock discontinuities. As the artificial viscosity, the density…

On the Consistency Restoring in SPH

2009

Smoothed particles hydrodynamics numerical simulations of droplets walking on viscous vibrating liquid

2016

We study the phenomenon of the "walking droplet", by means of numerical fluid dynamics simulations using the Smoothed Particle Hydrodynamics numerical method. This phenomenon occurs when a millimetric drop is released on the surface of an oil of the same composition, contained in a tank and subjected to vertical oscillations of frequency and amplitude very close to the Faraday instability threshold. At appropriate values of the parameters of the system under study, the oil droplet jumps permanently on the surface of the vibrating liquid forming a localized wave-particle system, reminding the behaviour of a wave particle quantum system as suggested by de Broglie. In our study, we made releva…

Inflow/outflow pressure boundary conditions for smoothed particle hydrodynamics simulations of incompressible flows

2017

Abstract Open Boundary treatment is a well-known issue in the Smoothed Particle Hydrodynamics (SPH) method, mainly when the truly Incompressible (ISPH) approach is employed. In the paper a novel method is proposed to set pressure boundary conditions in the computational domain inlets and outlets, without requiring the velocity profile assignment. The new technique allows to treat in the same way inflow and outflow sections, effectively dealing with the release of new particles at inlets and the deactivation of the ones leaving the domain through the outlets. Several 3D numerical tests, both in the laminar and turbulent regimes, are carried out to validate the proposed numerical scheme consi…