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101.
A. I. Leont'ev 《Fluid Dynamics》2002,37(4):512-529
The known methods of gas-dynamic temperature stratification are reviewed. Attention is concentrated on an analysis of the possibilities of the gas dynamic stratification method proposed by the author. The method is based on the difference between the equilibrium temperature of a thermally insulated wall in supersonic flow and the adiabatic stagnation temperature of the gas. Certain possible practical applications of the method to various types of energy-converting apparatus are considered. The basic trends of fundamental and applied research in the field of gas-dynamic temperature stratification are formulated. 相似文献
103.
Chiung‐Chiou Tsai Suh‐Yuh Yang 《Numerical Methods for Partial Differential Equations》2004,20(6):831-842
In this article we analyze the L2 least‐squares finite element approximations to the incompressible inviscid rotational flow problem, which is recast into the velocity‐vorticity‐pressure formulation. The least‐squares functional is defined in terms of the sum of the squared L2 norms of the residual equations over a suitable product function space. We first derive a coercivity type a priori estimate for the first‐order system problem that will play the crucial role in the error analysis. We then show that the method exhibits an optimal rate of convergence in the H1 norm for velocity and pressure and a suboptimal rate of convergence in the L2 norm for vorticity. A numerical example in two dimensions is presented, which confirms the theoretical error estimates. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004 相似文献
104.
Numerical solutions to the three-dimensional, unsteady, incompressible Reynolds-averaged Navier-Stokes equations have been obtained for bubble-type vortex breakdown. Two different turbulence models were employed: (1) standard K-ε and (2) an explicit, regularized algebraic Reynolds stress model. Results are computed at a Reynolds number of 10,000. The algebraic Reynolds stress model produced a breakdown bubble with a larger length-to-diameter ratio than did the K-ε model. Breakdown also occurred at lower levels of adverse pressure gradient for the algebraic stress model than for the K-ε model. In each case single-cell breakdown structures resulted. This is contrasted with numerical calculations for laminar breakdown which reveal the existence of complex multicell bubble breakdown structures. 相似文献
105.
In a linear medium an optical vortex induces the splitting of an edge dislocation into vortices of both topological charges. Their positions and number depend on which of the phase dislocations is shifted from the center of the host beam. Violations of the charge conservation law are discussed. 相似文献
106.
Chung Ho Liu 《国际流体数值方法杂志》2001,37(5):501-523
A new vortex particle‐in‐cell method for the simulation of three‐dimensional unsteady incompressible viscous flow is presented. The projection of the vortex strengths onto the mesh is based on volume interpolation. The convection of vorticity is treated as a Lagrangian move operation but one where the velocity of each particle is interpolated from an Eulerian mesh solution of velocity–Poisson equations. The change in vorticity due to diffusion is also computed on the Eulerian mesh and projected back to the particles. Where diffusive fluxes cause vorticity to enter a cell not already containing any particles new particles are created. The surface vorticity and the cancellation of tangential velocity at the plate are related by the Neumann conditions. The basic framework for implementation of the procedure is also introduced where the solution update comprises a sequence of two fractional steps. The method is applied to a problem where an unsteady boundary layer develops under the impact of a vortex ring and comparison is made with the experimental and numerical literature. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
107.
Haobin Yang Ziyu Wang Zhifeng Tu Junjie Jiang Danlin Xu Zhenwu Mo Haiqi Huang Dongmei Deng 《Annalen der Physik》2023,535(9):2300167
This paper analytically and numerically proposes the propagation dynamics of the symmetric Pearcey Gaussian vortex beam (SPGVB) in the uniformly moving parabolic potential. The optical vortex located in the initial plane produces a vortex channel in the presence of the uniformly moving parabolic potential, called the vortex trajectory. The vortex trajectory can be manipulated dynamically by configuring different combinations of the parameters, and the optical intensity and the focal position can also be affected. Moreover, the spatial dynamic vortex trajectory is derived analytically, and the 2D on-axis and off-axis vortex scenarios are also presented. Our work expands the methods of the vortex trajectory manipulation and may broaden more practical potential applications in the particle manipulation. 相似文献
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This paper proposes a method for simualting symmetric and simulating symmetric and asymmetric typhoonby using Rankine vortex model. Considering similarity between tropical cyclone andthe Rankine vortex,the paper has qualitatively discussed the feasibility of the methods In order to decide quantitatively Rankine vortex’s parameters to simulate typhoon’s structure, the paper has dealt with TCM data.for Yancy Typhoon (9012) as initial fields.. These results are considered as a foundation for further studying typhoon motion by CD approach. 相似文献