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The genus statistics is studied using large N -body simulations for several cosmological models. We consider the e ects of nonlinear gravitational evolution, smoothing the particle data in fully nonlinear regime, and the redshift-space distortion on the genus curve. Detailed comparison between the theoretical prediction in weakly nonlinear theory and the appropriate simulation results shows tha...

Horizontally periodic, vertically localized internal wavepackets evolve nonlinearly due only to interactions between the waves and their wave-induced mean flow. The corresponding weakly nonlinear equation that describes the evolution of the amplitude envelope before the onset of parametric subharmonic instability is examined. The results are compared with fully nonlinear numerical simulations a...

We rigorously derive weakly nonlinear relation between cosmic density and velocity fields up to third order in perturbation theory. The density field is described by the mass density contrast, δ. The velocity field is described by the variable θ proportional to the velocity divergence, θ = −f(Ω)−1H 0 ∇ · v, where f(Ω) ≃ Ω, Ω is the cosmological density parameter and H0 is the Hubble constant. O...

The formation of lee wakes and vortices is explored in the context of stratified flow with uniform basic-state wind and stability past elongated free-slip ridges. The theory of inviscid flow past a ridge of small nondimensional height e is revisited using a weakly nonlinear semianalytic model to compute flow fields through O(e2). Consistent with previous work, the weakly nonlinear solutions sho...

in this article, we develop the sinc-galerkin method based on double exponential transformation for solving a class of weakly singular nonlinear two-point boundary value problems with nonhomogeneous boundary conditions. also several examples are solved to show the accuracy efficiency of the presented method. we compare the obtained numerical results with results of the other existing methods in...

In this article, we develop the Sinc-Galerkin method based on double exponential transformation for solving a class of weakly singular nonlinear two-point boundary value problems with nonhomogeneous boundary conditions. Also several examples are solved to show the accuracy efficiency of the presented method. We compare the obtained numerical results with results of the other existing methods in...