1,599 research outputs found
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
Scaling and intermittency in ocean turbulence: analysis of coastal water optical properties and sea surface temperature (SST)
No full textWe consider here some scaling and intermittency properties of oceanic turbulence, with a general aim of considering the impact of turbulence on the bio-optical dynamics. For that purpose, we tried two different approaches, using in situ and satellite data. For the in situ study we adopted one dimensional and for the satellite two dimensional approaches. Different techniques such as Fourier power spectrum, Empirical mode of decomposition (EMD), Hilbert spectral analysis (HSA) have been used for analyzing the intermittency characteristics of the in situ data. For analyzing the multi-scale properties of the satellite images, we have considered Structure functions (SF) and Fourier power spectrum (1D and 2D). The general objective is to understand the multi-scale oceanic variability using scaling tools developed in the field of intermittent turbulence studies
On the Boundary Values of Harmonic Functions.
No full textOver the years many methods have been discovered to prove the existence of a solution of the Dirichlet problem for Laplace's equation. A fairly recent collection of proofs is based on representations of the Green's functions in terms of the Bergman kernel function or some equivalent linear operator [3]. Perhaps the most fundamental of these approaches involves the projection of an arbitrary function onto the class of harmonic functions in a Hilbert space whose norm is defined by the Dirichlet integral [5]. Here a problem has remained open concerning continuity at the boundary of the solution that is constructed by orthogonal projection. Past discussion of this question turned out to be successful in spaces of two or three dimensions, but failed for larger numbers of independent variables [2]. It is the purpose of the present note to remove any such restriction and simultaneously to give a concise treatment of the boundary condition that is applicable to other existence proofs
The organization of industry in the P.R. China: A new start or resort to old concepts?
No full textThe Chinese have let it be known since the death of Mao Zedong and the purge of the “Gang of Four” that they would in future draw on credits from foreign governments as well as other sources to finance imports of technology. According to western conjectures China’s capital requirements may be between US $ 25 and 50 bn or even a good deal higher. Many observers have taken the view that the Chinese have thereby put all their former development principles behind them. The author of the following article was in the P.R. China about the middle of this year at the invitation of the National Planning Commission. His assessment is that the P.R. China is far from embarking on an entirely new course in its development policy
Constant approximation for virtual backbone construction with guaranteed routing cost in wireless sensor networks
No full textNUMERICAL DESIGN OF TRANSONIC AIRFOILS**The work presented in this paper is supported by the AEC Computing and Applied Mathematics Center, Courant Institute of Mathematical Sciences, New York University, under Contract AT(30-1)-1480 with the U. S. Atomic Energy Commission.
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