Download or read book Numerical Simulations of Stratified Fluid Flow Over Topography Near Resonance written by Harmony Rose Brown and published by . This book was released on 2008 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use a high-resolution spectral numerical scheme to solve the two-dimensional equations of motion for the flow of a uniformly stratified Boussinesq fluid over isolated bottom topography in a channel of finite depth. The focus is on conditions such that the flow is near linear resonance. The results are compared with the analytic solutions as well as experimental tank results. We also analyze the approach to breaking that occurs downstream of the topography near resonance.

Download or read book Numerical simulations of uniformly stratified fluid flow over topography written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Topographic Effects in Stratified Flows written by Peter G. Baines and published by Cambridge University Press. This book was released on 2022-01-27 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore the nature of density-stratified flow over and around topography, including applications to the flow of the atmosphere and ocean.

Download or read book Simulation of Stratified Turbulent Flows in Complex Geometry written by Narsimha Reddy Rapaka and published by . This book was released on 2015 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct and Large Eddy Simulation approaches are used to study internal tide generation and turbulence at a model topography. A three dimensional finite difference code using an immersed boundary method is developed to simulate stratified turbulent flows over complex geometry on a Cartesian grid. The thesis is comprised of two phases. In the first phase, a mixed spectral/finite difference code is used to solve the governing equations in generalized coordinates. Direct and large eddy simulations are performed using a body fitted grid (BFG) to study the internal waves generated by the oscillation of a barotropic tide over a model ridge of triangular shape. The objective is to assess the role of nonlinear interactions including turbulence in situations with low tidal excursion number. The criticality parameter, defined as the ratio of the topographic slope to the characteristic slope of the tidal rays, is varied from subcritical to supercritical values. The barotropic tidal forcing is also systematically increased. In laminar flow at low forcing, numerical results of the energy conversion agree well compared to linear theory in subcritical and supercritical cases but not at critical slope angle. In critical and supercritical cases with higher forcing, there are convective overturns, turbulence and significant reduction (as much as 25%) of the radiated wave flux with respect to laminar flow results. The phase dependence of turbulence within a tidal cycle is examined and found to differ substantially between the ridge slope and the ridge top where the beams from the two sides cross. In the second phase, a sharp-interface Immersed Boundary Method (IBM) is developed to simulate high Reynolds number density-stratified turbulent flows in complex geometry. The basic numerical scheme corresponds to a central second-order finite difference method, third-order Runge-Kutta integration for the advective terms and an alternating direction implicit (ADI) scheme for the viscous and diffusive terms. Both direct numerical simulation (DNS) and large eddy simulation (LES) approaches are considered. The focus is on accurate computation of the internal gravity wave field and turbulence near an underwater obstacle in a model problem where a tide oscillates over the obstacle. Methods to enhance the mass conservation and numerical stability of the solver to simulate high Reynolds number flows are discussed. The solver is validated using Direct Numerical Simulations (DNS) of channel flow with and without stratification, and tidal flow over a laboratory-scale (order of few meters) smoothed triangular ridge. The results including baroclinic energy flux, mean flow properties and turbulent kinetic energy agree reasonably well with our previous results obtained using a body-fitted grid (BFG). The deviation of IBM results from BFG results is found to increase with increasing steepness of the topography relative to the internal wave propagation angle. LES is performed on a large scale ridge, of the order of few kilometers in length, at significantly larger Reynolds number. A non-linear drag law is utilized to parameterize turbulent losses due to bottom friction. The large scale problem exhibits qualitatively similar behavior to the laboratory scale problem with some differences: slightly larger intensification of the boundary flow and somewhat higher nondimensional values for conversion, baroclinic wave flux and turbulent kinetic energy. The phasing of wave breaking and turbulence exhibits little difference between small and large scale obstacles. We conclude that IBM is a viable approach to the simulation of internal waves and turbulence in high Reynolds number stratified flows over topography.

Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Stably Stratified Flow Over Hills written by Roderick Johnstone and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Shallow Flows written by Gerhard H. Jirka and published by Taylor & Francis. This book was released on 2004-09-15 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text presents the key findings of the International Symposium held in Delft in 2003, which explored the process of shallow flows. Shallow flows are found in lowland rivers, lakes, estuaries, bays, coastal areas and in density-stratified atmospheres, and may be observed in puddles, as in oceans. They impact on the life and work of a wide variety of readers, who are here provided with a clear overview of the subject. Shallow flows are intrinsically turbulent. On one hand, there are strongly three-dimensional, small-scale turbulent motions and on the other hand, large-scale quasi-two-dimensional turbulence. This book explains and examines these differences and their effects with sections on transport processes in shallow flows; shallow jets, wakes and mixing layers; stratified and rotating flows in ocean and atmosphere; river and channel flows; and numerical modelling and turbulence closure techniques. The reader is provided with the pick of current studies and a fresh approach to the subject, with expert examination of a fascinating and crucial phenomenon of our world's water systems.

Download or read book Numerical Simulation of Unsteady Flows and Transition to Turbulence written by O. Pironneau and published by Cambridge University Press. This book was released on 1992-07-31 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: The workshop concentrated on the following turbulence test cases: T1 Boundary layer in an S-shaped duct; T2 Periodic array of cylinders in a channel; T3 Transition in a boundary layer under the influence of free-stream turbulence; T4 & T5: Axisymmetric confined jet flows.

Download or read book Flow of Nonuniformly Stratified Fluid of Large Depth Over Topography written by Kevin Scott Davis and published by . This book was released on 1999 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Marine Structures written by Erkan Oterkus and published by MDPI. This book was released on 2020-01-31 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural mechanics is an important field of engineering. The main goal of structural mechanics is to ensure that structures are safe and durable so that catastrophic situations can be prevented, which can otherwise cause loss of life, environmental pollution and financial losses. Depending on the uses of the structure and the conditions that the structure is subjected to, special treatment may be required for the analysis. Specifically, marine structures are subjected to harsh environmental conditions due to the marine environment, which can cause several different damage mechanisms including fatigue and corrosion. This book on “Marine structures” considers a wide range of areas related to marine structures and provides a compilation of numerical and experimental studies related to “Marine structures” research.

Download or read book Proceedings written by and published by . This book was released on 2004 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Stratified Flow written by Xiaohong Wang and published by . This book was released on 2000 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Geometric Modelling Numerical Simulation and Optimization written by Geir Hasle and published by Springer Science & Business Media. This book was released on 2007-06-10 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited volume addresses the importance of mathematics for industry and society by presenting highlights from contract research at the Department of Applied Mathematics at SINTEF, the largest independent research organization in Scandinavia. Examples range from computer-aided geometric design, via general purpose computing on graphics cards, to reservoir simulation for enhanced oil recovery. Contributions are written in a tutorial style.

Download or read book The Role of Background Flow Variations in Stratified Flows Over Topography written by Ivan Skopovi and published by . This book was released on 2006 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the atmosphere and oceans feature density variations with depth, the flow of a density-stratified fluid over topography is central to various geophysical and meteorological applications and has been studied extensively. For reasons of convenience and mathematical tractability, the majority of theoretical treatments of stratified flow over a finite-amplitude obstacle assume idealized background flow conditions, namely constant free-stream velocity and either a homogeneous or two-layer buoyancy-frequency profile. In this work, a numerical model is developed that accounts for general variations in the buoyancy-frequency profile far upstream and the presence of unsteadiness in the free-stream velocity. The model employs a second-order projection method for solving the Euler equations for stratified flow over locally confined topography in a horizontally and vertically unbounded domain - the flow configuration most pertinent to atmospheric applications - combined with absorbing viscous layers at the upper and lateral boundaries of the computational domain. Using this model, a study is first made of the effect of variations in the buoyancy frequency on the generation of mountain gravity waves.

Download or read book Journal of Physical Oceanography written by and published by . This book was released on 2005 with total page 1204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stratified Flow Over Topography The Role of Small Scale Entrainment and Mixing in Flow Establishment written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stratified flow over topography is examined in the context of its establishment from rest. A key element of numerical and steady state analytical solutions for large amplitude topographic flow is the splitting of streamlines which then enclose a trapped wedge of mixed fluid above the rapidly moving deeper layer. Measurements have been acquired which show that this wedge arises from small scale instabilities and mixing formed initially by the acceleration of subcritical stratified flow over the obstacle crest. The volume of trapped fluid progressively increases with time, permitting the primary flow to descend beneath it over the lee face of the obstacle. Throughout the evolution of this flow, small scale instability and consequent entrainment is the mechanism responsible for producing the weakly stratified wedge, thus allowing establishment of the downslope flow to take place. Velocity structure of instabilities within the entrainment zone is observed and the associated entrainment rate determined. The entrainment is sufficient to produce a slow downstream motion within the upper layer and a density step between the layers that decreases with downstream distance. The resulting internal hydraulic response is explained in terms of a theory which accommodates the spatially variable density difference across the sheared interface. The measurements described here were acquired in a coastal inlet subject to gradually changing tidal currents. It is proposed that the observed mechanism for flow establishment also has application to atmospheric flow over mountains.