Search results for "Fluid Dynamic"
showing 10 items of 1034 documents
Acoustic rendering of particle-based simulation of liquids in motion
2009
In interaction and interface design, the representation of continuous processes often uses liquid metaphors, such as dripping or streaming. When an auditory display of such processes is required, an approach to sound-synthesis based on the physics of liquids in motion would be the most convincing, especially when real-time interaction is into play. In order to bridge the complexity of fluid-dynamic simulations with the needs of interactive sonification, we propose a multi-rate sound synthesis of liquid phenomena. Low-rate smoothed-particle hydrodynamics is used to model liquids in motion and to trigger sound-emitting events. Such events, such as solid-liquid collision, or bubble formation, …
First Results of the Testing of the Liquid Gallium Jet Limiter Concept for ISTTOK
2006
The use of liquid metals as plasma facing components in tokamaks has recently experienced a renewed interest stimulated by their advantages to the development of a fusion reactor. Liquid metals have been proposed to solve problems related to the erosion and neutronic activation of solid walls submitted to high power loads allowing an efficient heat exhaustion from fusion devices. Presently the most promising materials are Lithium and Gallium. ISTTOK, a small size tokamak, will be used to test the behavior of a liquid Gallium jet in the vacuum chamber and its influence on the plasma. This paper presents a description of the conceived setup as well as experimental results. The liquid Gallium …
Interaction of a liquid gallium jet with the tokamak ISTTOK edge plasma
2008
Abstract The interaction of a liquid gallium jet with plasma has been investigated in the tokamak ISTTOK. This paper presents a description of the conceived experimental setup, a detailed characterization of the produced jets and the first experimental results related to the gallium–plasma interaction. A stable jet has been obtained, which was not noticeably affected by magnetic field transients. ISTTOK has been successfully operated with the gallium jet without degradation of the discharge or a significant plasma contamination by liquid metal. This observation is supported by spectroscopic measurements showing that gallium radiation is limited to the region around the jet. Furthermore, the…
Large eddy simulation of inertial particles dispersion in a turbulent gas-particle channel flow bounded by rough walls
2020
The purpose of this paper is to understand the capability and consistency of large eddy simulation (LES) in Eulerian–Lagrangian studies aimed at predicting inertial particle dispersion in turbulent wall-bounded flows, in the absence of ad hoc closure models in the Lagrangian equations of particle motion. The degree of improvement granted by LES models is object of debate, in terms of both accurate prediction of particle accumulation and local particle segregation; therefore, we assessed the accuracy in the prediction of the particle velocity statistics by comparison against direct numerical simulation (DNS) of a finer computational mesh, under both one-way and two-way coupling regimes. We p…
Zero Viscosity Limit for Analytic Solutions, of the Navier-Stokes Equation on a Half-Space.¶I. Existence for Euler and Prandtl Equations
1998
This is the first of two papers on the zero-viscosity limit for the incompressible Navier-Stokes equations in a half-space. In this paper we prove short time existence theorems for the Euler and Prandtl equations with analytic initial data in either two or three spatial dimensions. The main technical tool in this analysis is the abstract Cauchy-Kowalewski theorem. For the Euler equations, the projection method is used in the primitive variables, to which the Cauchy-Kowalewski theorem is directly applicable. For the Prandtl equations, Cauchy-Kowalewski is applicable once the diffusion operator in the vertical direction is inverted.
Zero Viscosity Limit for Analytic Solutions of the Navier-Stokes Equation on a Half-Space.¶ II. Construction of the Navier-Stokes Solution
1998
This is the second of two papers on the zero-viscosity limit for the incompressible Navier-Stokes equations in a half-space in either 2D or 3D. Under the assumption of analytic initial data, we construct solutions of Navier-Stokes for a short time which is independent of the viscosity. The Navier-Stokes solution is constructed through a composite asymptotic expansion involving the solutions of the Euler and Prandtl equations, which were constructed in the first paper, plus an error term. This shows that the Navier-Stokes solution goes to an Euler solution outside a boundary layer and to a solution of the Prandtl equations within the boundary layer. The error term is written as a sum of firs…
Experimental and numerical investigation of the leading edge sweep angle effect on the performance of a delta blades hydrokinetic turbine
2020
Abstract In the last decades, an increase of energy consumption has been noted around the world. Hence, the excessive use of fossil fuels can lead to serious environmental concerns. Indeed, the use of renewable energy sources is needed to reduce the greenhouse gas effects and the CO2 emissions in the atmosphere. Small-scale hydropower could be an interesting and renewable alternative solution. The cross-flow turbines present several advantages compared to the axial-flow turbines. Therefore, increasing efforts are taken to enhance the efficiency and extend the applicability of the cross-flow turbines. In this paper, experimental investigation was carried out to evaluate the performance of a …
Modeling Atmospheric Turbulence via Rapid Distortion Theory: Spectral Tensor of Velocity and Buoyancy
2017
Abstract A spectral tensor model is presented for turbulent fluctuations of wind velocity components and temperature, assuming uniform vertical gradients in mean temperature and mean wind speed. The model is built upon rapid distortion theory (RDT) following studies by Mann and by Hanazaki and Hunt, using the eddy lifetime parameterization of Mann to make the model stationary. The buoyant spectral tensor model is driven via five parameters: the viscous dissipation rate ε, length scale of energy-containing eddies L, a turbulence anisotropy parameter , gradient Richardson number (Ri) representing the local atmospheric stability, and the rate of destruction of temperature variance . Model outp…
Numerical prediction of ventilated planing flat plates for the design of Air Cavity Ships
2017
In recent years, a great world issue is the respect for the environment. Each researcher, in his competence field, proposes new technologies and new approaches in order to reduce the environmental impact of a product or of an industrial process. In the naval field, the main way in order to reduce the environmental impact of the ship during the navigation is the reduction of the drag resistance and so the reduction of requested power. There are many ways in order to obtain a reduction of drag. This paper investigates, with a preliminary numerical study by means of Computational Fluid Dynamics (CFD), the Air Cavity Ships technology (ACS). A first part of the paper concerns the study of the ri…
Gravitational flow of a thin film of liquid metal in a strong magnetic field
2014
Abstract The influence of a poloidal magnetic field of the spherical Tokamak on super thin (h ≈ 0.1 mm) film flow of liquid metal driven by gravity over the surface of the cooled divertor plate is addressed. The experimental setup developed at the Institute of Physics, University of Latvia (IPUL) is described, which makes it possible to drive and visualize such liquid metal flows in the solenoid of the superconducting magnet “Magdalena”. As applied to the above setup, the magnetic field effect on the operation of the capillary system of liquid metal flow distribution (CSFD) is evaluated by using molten metal (lithium or eutectic InGaSn alloy) with a very small linear flowrate q ≤ 1 mm2/s, s…