On the Use of Fractional Brownian Motion Simulations to Determine the Three-dimensional Statistical Properties of Interstellar Gas
نویسندگان
چکیده
Based on fractional Brownian motion (fBm) simulations of three-dimensional gas density and velocity fields, we present a study of the statistical properties of spectroimagery observations (channel maps, integrated emission, and line centroid velocity) in the case of an optically thin medium at various temperatures. The power spectral index W of the integrated emission is confirmed to be that of the threedimensional density field ( n) provided that the medium’s depth is at least of the order of the largest transverse scale in the image, and the power spectrum of the centroid velocity map is found to have the same index C as that of the velocity field ( v). Further tests with non-fBm density and velocity fields show that this last result holds and is not modified by the effects of density-velocity correlations. A comparison is made with the theoretical predictions of Lazarian & Pogosyan. Subject headings: ISM: structure — methods: numerical — methods: statistical — turbulence
منابع مشابه
M.-A. Miville-Deschênes
On the use of fractional Brownian motion simulations to determine the 3D statistical properties of interstellar gas. ABSTRACT Based on fractional Brownian motion (fBm) simulations of 3D gas density and velocity fields, we present a study of the statistical properties of spectro-imagery observations (channel maps, integrated emission, and line centroid velocity) in the case of an optically thin ...
متن کاملThree dimensional numerical study on a trapezoidal microchannel heat sink with different inlet/outlet arrangements utilizing variable properties nanofluid
Nowadays, microchannels as closed circuits channels for fluid flow and heat removal are an integral part of the silicon-based electronic microsystems. Most of previous numerical studies on microchannel heat sinks (MCHS) have been performed for a two-dimensional domain using constant properties of the working fluid. In this study, laminar fluid flow and heat transfer of variable properties Al2O3...
متن کاملExistence and Measurability of the Solution of the Stochastic Differential Equations Driven by Fractional Brownian Motion
متن کامل
On time-dependent neutral stochastic evolution equations with a fractional Brownian motion and infinite delays
In this paper, we consider a class of time-dependent neutral stochastic evolution equations with the infinite delay and a fractional Brownian motion in a Hilbert space. We establish the existence and uniqueness of mild solutions for these equations under non-Lipschitz conditions with Lipschitz conditions being considered as a special case. An example is provided to illustrate the theory
متن کاملCFD simulations on natural convection heat transfer of alumina-water nanofluid with Brownian motion effect in a 3-D enclosure
The CFD simulation has been undertaken concerning natural convection heat transfer of a nanofluid in vertical square enclosure, whose dimension, width height length (mm), is 40 40 90, respectively. The nanofluid used in the present study is -water with various volumetric fractions of the alumina nanoparticles ranging from 0-3%. The Rayleigh number is . Fluent v6.3 is used to simulate nanofluid ...
متن کامل