1993/10/20 by Paul J. Mancinelli, Amos Yahil, A. Yahil +6
Earth and Planetary Sciences · Economics, Econometrics and Finance · Mathematics · Physics and Astronomy · #Applied mathematics #Astrophysics (astro-ph) #Boundary value problem #Cosmology and Gravitation Theories #Density ratio #FOS: Physical sciences #Gaussian #Mathematical analysis #Mathematics #Mechanics #Meteorological Phenomena and Simulations #Nonlinear system #Perturbation (astronomy) #Physics #Quantum mechanics #Smoothing #Statistical physics #Statistics #Stochastic processes and financial applications #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9310038
paper for the 9th IAP Meeting, Paris, July 1993: "Cosmic Velocity Fields". 6 pages of uuencoded compressed postscript; figures included. SUSB0193
arxiv created 1993/10/20 · openalex publication_date 1993/10/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Nonlinear approximations to problems with mixed boundary conditions are useful for predicting large-scale streaming velocities from the density field, or vice-versa. We evaluate the schemes of Bernardeau \citebernardeau92, Gramann \citegramann93, and Nusser \etal \citenusser91, using smoothed density and velocity fields obtained from N-body simulations of a CDM universe. The approximation of Nusser \etal is overall the most accurate and robust. For Gaussian smoothing of 1000\kms the mean error in the approximated relative density perturbation, δ, is smaller than 0.06, and the dispersion is 0.1. The \rms error in the estimated velocity is smaller than 60\kms, and the dispersion is 40\kms. For smoothing of 500\kms these numbers increase by about a factor ∼ 2 for δ< 4-5, but deteriorate at higher densities. The other approximations are comparable to those of Nusser \etal for smoothing of 1000\kms, but are much less successful for the smaller smoothing of 500\kms.