이정일 교수

In this study, we investigate the applicability of the mean wall shear stress as a boundary condition for large eddy simulation of wall-bounded turbulent flow with coarse-grid resolution near the wall. We consider turbulent channel flow up to Reτ = O(108) and turbulent boundary layer flow up to Reθ = O(107). The mean wall shear stress is determined based on the log-law at every time step. It is shown that the mean wall shear stress boundary condition accurately predicts the logarithmic velocity

In the present study, the dynamic subgrid-scale eddy viscosity models with a global model coefficient by Park et al. [Phys. Fluids 18, 125109 (2006)] (called dynamic global models hereafter) are applied to large eddy simulation of decaying isotropic turbulence to examine their performances in transient flow. The dynamic global model based on the global equilibrium between the subgrid-scale dissipation and the viscous dissipation fails to predict the temporal behavior of decaying isotropic turbul

Multiple logistic regression is an accepted statistical method for assessing association between an anticedant characteristic (risk factor) and a quantal outcome (probability of disease occurrence), statistically adjusting for potential confounding effects of other covariates. Yet the method has potential drawbacks which are not generally recognized. This article considers one important drawback of logistic regression. Specifically the so-called main effect logistic model assumes that the probab

We determine the leading-order nonrelativistic quantum chromodynamics (NRQCD) matrix element 〈O1〉ϒ and the ratio 〈q2〉ϒ, for ϒ=ϒ(nS) with n=1, 2, and 3 by comparing the measured values for Γ[ϒ→e+e−] with the NRQCD factorization formula in which relativistic corrections are resummed to all orders in the heavy-quark velocity v. The values for 〈q2〉ϒ, which is the ratio of order-v2 matrix element to 〈O1〉ϒ, are new. They can be used for NRQCD predictions involving ϒ(nS) and ηb(nS) with relativistic co

This paper analyzes the temperature distribution of an induction motor in steady state using a hybrid thermal network method-finite element method (TNM-FEM). 3 dimensional FEM has been used to analyze the thermal stresses on the rotor of an induction motor. The mechanical deformations and thermal stress distributions are obtained. The numerical analyzes of the thermal field are verified by experimental results.

We illustrate a rigorous approach to express the totally symmetric isotropic tensors of arbitrary rank in the $n$-dimensional Euclidean space as a linear combination of products of Kronecker deltas. By making full use of the symmetries, one can greatly reduce the efforts to compute cumbersome angular integrals into straightforward combinatoric counts. This method is generalized into the cases in which such symmetries are present in subspaces. We further demonstrate the mechanism of the tensor-in

This paper proposes a new color halftone image quality assessment method based upon the color structural similarity measure with considering the human visual characteristics. To include the color visual characteristics, we carry out the color filtering for each luminance, redgreen, and blue-yellow channels. Then, we apply the color structural similarity measure to the color filtered images, which are the reference image and the halftoned image, to evaluate the localized structural difference. By

The delaminations are assumed to extend through the width of the composite. A finite element method based on a layer-wise plate theory is developed

Abstract We compute the electrostatic potential of a uniformly charged triangle. Barycentric coordinates are employed to express the field point, the parametrization of the surface integral, and the gradient operator. The resultant analytic expression for the electrostatic potential is expressed in terms of the side lengths of the triangle, the altitude of the field point from the plane in which the triangle is placed, and the barycentric coordinates of the field point relative to the triangle.