Structure of nonnegative nontrivial and positive solutions was precisely studied for some singularly perturbed p-Laplace equations. By virtue of sub- and supersolution method, it is shown that there are many nonnegati...Structure of nonnegative nontrivial and positive solutions was precisely studied for some singularly perturbed p-Laplace equations. By virtue of sub- and supersolution method, it is shown that there are many nonnegative nontrivial spike-layer solutions and positive intermediate spike-layer solutions. Moreover, the upper and lower bound on the measure of each spike-layer were estimated when the parameter is sufficiently small.展开更多
Interactions between different scales in turbulence were studied starting from the incompressible Navier-Stokes equations. The integral and differential formulae of the short-range viscous stresses, which express the ...Interactions between different scales in turbulence were studied starting from the incompressible Navier-Stokes equations. The integral and differential formulae of the short-range viscous stresses, which express the short-range interactions between contiguous scales in turbulence,were given. A concept of the resonant-range interactions between extreme contiguous scales was introduced and the differential formula of the resonant-range viscous stresses was obtained. The short- and resonant-range viscous stresses were applied to deduce the large-eddy simulation (LES) equations as well as the multiscale equations, which are approximately closed and do not contain any empirical constants or relations. The properties and advantages of using the multiscale equations to compute turbulent flows were discussed. The short-range character of the interactions between the scales in turbulence means that the multiscale simulation is a very valuable technique for the calculation of turbulent flows. A few numerical examples were also given.展开更多
An online method of identification of dynamic characteristics only using measured ambient response of structural dynamic system is widely focused on.The Ibrahim and ARMA (AutoRegressive Moving Average) methods are bas...An online method of identification of dynamic characteristics only using measured ambient response of structural dynamic system is widely focused on.The Ibrahim and ARMA (AutoRegressive Moving Average) methods are basic identification methods.A model on dynamic system suffered by random ambient excitation was researched into, and a subspace decomposition method being different from traditional harmonic retrieval method was introduced.Robustness and effectiveness of this approach on identification of vibration characteristics are demonstrated on numerical experiment.展开更多
文摘Structure of nonnegative nontrivial and positive solutions was precisely studied for some singularly perturbed p-Laplace equations. By virtue of sub- and supersolution method, it is shown that there are many nonnegative nontrivial spike-layer solutions and positive intermediate spike-layer solutions. Moreover, the upper and lower bound on the measure of each spike-layer were estimated when the parameter is sufficiently small.
文摘Interactions between different scales in turbulence were studied starting from the incompressible Navier-Stokes equations. The integral and differential formulae of the short-range viscous stresses, which express the short-range interactions between contiguous scales in turbulence,were given. A concept of the resonant-range interactions between extreme contiguous scales was introduced and the differential formula of the resonant-range viscous stresses was obtained. The short- and resonant-range viscous stresses were applied to deduce the large-eddy simulation (LES) equations as well as the multiscale equations, which are approximately closed and do not contain any empirical constants or relations. The properties and advantages of using the multiscale equations to compute turbulent flows were discussed. The short-range character of the interactions between the scales in turbulence means that the multiscale simulation is a very valuable technique for the calculation of turbulent flows. A few numerical examples were also given.
文摘An online method of identification of dynamic characteristics only using measured ambient response of structural dynamic system is widely focused on.The Ibrahim and ARMA (AutoRegressive Moving Average) methods are basic identification methods.A model on dynamic system suffered by random ambient excitation was researched into, and a subspace decomposition method being different from traditional harmonic retrieval method was introduced.Robustness and effectiveness of this approach on identification of vibration characteristics are demonstrated on numerical experiment.
