The present research is comprised of theoretical investigations of three problems in the mechanics of internal waves of large amplitude, using analysis and numerical methods. In the first problem, the flow of a Boussinesq density-stratified fluid of large depth past the algebraic mountain ('Witch of Agnesi') is studied in the hydrostatic limit using the asymptotic theory of Kantzios & Akylas (1...

In this paper, the transverse vibration of a triple-walled carbon nanotube (TWCNT) conveying fluid flow is studied based on the strain/inertia gradient theory with van der Waals interaction taken into consideration. The nanotube is modelled using Euler-Bernoulli beam model and the Galerkin’s method is employed to obtain the CNT complex valued Eigen-frequencies. The effects of the fluid flow tho...

Abstract

Regimes of convective entrainment in linearly and discretely stratified fluids are investigated by means of a high-resolution LES in conjunction with relevant data from atmospheric, laboratory, numerical, and analytical studies of penetrative convection. Relationships between parameters of entrainment in the discretely stratified fluid are shown to be rather different to their counterparts in t...

The strength of diapycnal mixing by small-scale motions in a stratified fluid is investigated through changes to the mean buoyancy profile. We study the mixing in laboratory experiments in which an initially linearly stratified fluid is stirred with a rake of vertical bars. The flow evolution Ž . depends on the Richardson number Ri , defined as the ratio of buoyancy forces to inertial forces. A...

Internal waves in the atmosphere and ocean are generated frequently from the interaction of mean flow with bottom obstacles such as mountains and submarine ridges. Analysis of these environmental phenomena involves theoretical models of non-homogeneous fluid affected by the gravity. In this paper, a semi-analytical model of stratified flow over the mountain range is considered under the assumpt...

In this paper we discuss a theoretical model for the interfacial profiles of progressive non-linear waves which result from introducing a triangular obstacle, of finite height, attached to the bottom below the flow of a stratified, ideal, two layer fluid, bounded from above by a rigid boundary. The derived equations are solved by using a nonlinear perturbation method. The dependence of the inte...

Direct numerical simulations of the time evolution of homogeneous stably stratified shear flows have been performed for mean flow Richardson numbers in the range from 0.075 to 1.00 and for Prandtl numbers ranging from 0.1 to 2. The local or instantaneous results indicate that when the turbulent Froude number FrT = 1 the peak value of mixing efficiency is Rf ≈ 0.25, a result independent of the P...

This paper revisits the classical problem of convectively driven one-dimensional (parallel) flow along an infinite vertical plate. We consider flows induced by an impulsive (step) change in plate temperature, a sudden application of a plate heat flux, and arbitrary temporal variations in plate temperature or plate heat flux. Provision is made for pressure work and vertical temperature advection...