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Science China Mathematics 2022年第12期65卷 2631-2656页

作者： Chuanjun Chen Xiaofeng Yang School of Mathematics and Information Sciences Yantai UniversityYantai 264005China Department of Mathematics University of South CarolinaSC29208USA

For the variable-density/viscosity Cahn-Hilliard phase-field model of the binary-phase incompressible fluid flow system, the development of easy-to-implement numerical schemes has long been known as a challenging problem. We develop a novel fully-decoupled numerical technique in this article which can achieve unconditional energy stability while explicitly discretizing nonlinear coupling items. The idea is invented on the basis of combining the Strang operator splitting method and the novel decoupling method by using the zero-energy-contribution property. The scheme only needs to solve a series of completely independent linear elliptic equations at each time step, in which the Cahn-Hilliard equation and the pressure Poisson equation are with constant coefficients. To demonstrate the effectiveness of the scheme, we provide the rigorous proof of the energy stability/solvability, and also perform ample accuracy and stability tests and 2D/3D numerical simulations, including the Rayleigh-Taylor instability and bubble rising dynamics.

关键词： variable-density decoupled time marching Cahn-Hilliard equation Navier-Stokes equations energy stability

STUDY ON THE METHOD OF CONSTRUCTING variable-density YIELD TABLE

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Journal of Northeast Forestry University 1991年第2期2卷 95-99页

作者： Lee Longchang Hao Wenkang Weng Guoqing Northeast Forestry University 1. Northeast Forestry University China

Growth of stand average DBH is discussed bassed on relationship between standgrowth and stand *** equation of stand average DBH is fitted with data of 65 plotsand 130 stem analyses of site index 18 meter of old-growth Larch(Larix gmeliniiRupr.)collectedin Great Xing’an Mountain m Inner ***-density yield tables of old—growth Larchare constructed based on growth equation of stand average DBH and relationship between standaverage DBH and the other stand attributes.

关键词： Dahurian larch Stand density variable-density yield table

Three-dimensional mathematical model of river bed erosion by float open caisson in construction period

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Science China Mathematics 1995年第5期38卷 618-626,641页

作者：方红卫 Department of Hydraulic and Electric Engineering Tsinghua Univeisity Beijing 100084 China)

The basic governing equations and boundary conditions are deduced in general curve coordination system from natural variable-density turbulence which is two-phase flow with sediment. A new 27-point three-dimensional finite analytic discretization scheme and competent velocity formula for non-uniform bed material are applied to the calculation of the float open caisson in construction period. It is shown that good accuracy and adaptation are obtained in the calculation of two-phase flow with sediment and variable-density as well as complex boundary.

关键词： variable-density turbulence coordinate transformation exposition height

The application of combined gravity and seismic data formation separation for revealing deep structure

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Applied Geophysics 2006年第4期3卷 255-259页

作者： WeiYan Yang Zhanjun BGP CNPC Zhuozhou 072751 China

In some oilfields with 3D seismic data, the deeper structure cannot be observed due to poor quality deep seismic data. Layer stripping using both seismic and gravity data is a solution for this problem but it cannot get satisfactory results because the horizontal variations in formation density are ignored. We present a variable-density formation separation technique to address this problem. Based on 3D seismic depth data and laterallyvariable density derived from 3D seismic velocity data, the upper formation gravity effect is calculated by forward modeling and removed from the Bouguer gravity. The formation-separated gravity anomaly with variable density is obtained, which mainly reflects the deeper geological structure. In block XX of North Africa, the shallow formations seismic data is excellent but the data at the top of basement is poor. The formation-separated gravity anomaly processed under the control of 3D seismic data fits well with the known seismic interpretation and wells. It makes the geological interpretation more reliable.

关键词： Formation separation technique variable-density