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71.
72.
This work is concerned with 2D-Navier Stokes equations in a multiply-connected bounded domain with permeable walls. The permeability is described by a Navier type condition. Our aim is to show that the inviscid limit is a solution of the Euler equations, satisfying the Navier type condition on the inflow zone of the walls. 相似文献
73.
Yuzuru Eguchi 《国际流体数值方法杂志》2001,37(3):279-295
Two practical techniques are proposed in this paper to simulate a flow contained in a plenum with a downstream tube bundle under a PC environment. First, a technique to impose slip wall conditions on smooth‐faced planes and sharp edges is proposed to compensate for the mesh coarseness relative to boundary layer thickness. In particular, a new type of Poisson equation is formulated to simultaneously satisfy both such velocity boundary conditions on walls and the incompressibility constraint. Second, a numerical model for a downstream tube bundle is proposed, where hydraulic resistance in a tube is imposed as a traction boundary condition on a fluid surface contacting the tube bundle end. The effectiveness of the techniques is numerically demonstrated in the application to a flow in a condenser water box. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
74.
75.
A mechanical device specially designed for the application of low-level post-tensioning forces to glass fiber reinforced polymer
(GFRP) bars has been developed at the University of Missouri-Rolla. Some of the advantageous features of this device are that
it is simple to assemble and the low-level post-tensioning forces can be applied manually and safely without the need for
hydraulic jacks or heavy equipment. This device has been conceived with the main objective of retrofitting masonry buildings,
some of which remain in service despite large, open cracks leading to considerable instability and serviceability concerns.
According to the method derived in this paper, GFRP bars are installed in artificially imposed grooves and then post-tensioned
with low-level stresses with the main objective to partially close these cracks, such that the serviceability and in-plane
capacity of un-reinforced masonry (URM) buildings may be regained. In this paper we describe the mechanical components of
this device, along with its advantageous features and potential application for the retrofit of URM walls. 相似文献
76.
77.
Hironobu Sakagawa 《Journal of statistical physics》2007,129(3):537-553
We consider the d(≥3)-dimensional Gaussian lattice field confined between two hard walls. We show that the field becomes massive and identify
the precise asymptotic behavior of the mass and the variance of the field as the height of the wall goes to infinity. 相似文献
78.
采用黏性激波层基本方程组对有无泰氟龙烧蚀两种情况下的钝锥体化学非平衡绕流作了数值求解,以研究泰氟龙烧蚀对流场电子密度的影响规律.算例结果表明:泰氟龙烧蚀确有降低流场电子密度的效应.平衡催化壁工况下这种效应的强度,显著大于非催化壁工况下的强度;远下游截面处的这种效应的强度,显著大于驻点区的强度.此外,通过计算结果分析,对形成上述影响规律的原因作了初步讨论. 相似文献
79.
This article presents an experimental study of the vibro-acoustic response of a pipe excited by a fully-developed turbulent
air flow. First, the wall pressure field acting on the internal pipe wall is investigated. The power spectral density of the
wall pressure fluctuations is analyzed after cancellation of contaminating background noise. The convection velocity and correlation
lengths are calculated from measured cross-spectra, and the cross-spectra are expressed in Corcos model form. Second, the
vibro-acoustic response of the pipe is analyzed by referring to the structural modes of the pipe.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
80.