常平均流量分层介质地层中重力波方程的格林修正函数

Drainage in a model stratified porous medium

We show that when a non-wetting fluid drains a stratified porous medium at sufficiently small capillary numbers Ca, it flows only through the coarsest stratum of the medium; by contrast, above a threshold Ca, the non-wetting fluid is also forced laterally, into part of the adjacent, finer strata. The spatial extent of this partial invasion increases with Ca. We quantitatively understand this behavior by balancing the stratum-scale viscous pressure driving the flow with the capillary pressure required to invade individual pores. Because geological formations are frequently stratified, we antici…

Forced Imbibition in Stratified Porous Media

Imbibition plays a central role in diverse energy, environmental, and industrial processes. In many cases, the medium has multiple parallel strata of different permeabilities; however, how this stratification impacts imbibition is poorly understood. We address this gap in knowledge by directly visualizing forced imbibition in three-dimensional (3D) porous media with two parallel strata. We find that imbibition is spatially heterogeneous: for small capillary number Ca, the wetting fluid preferentially invades the fine stratum, while for Ca above a threshold value, the fluid instead preferential…

各向异性流体中梯度格林涡的 stencil 配置、强迫方案和分辨率影响的系统评估：一个格子玻尔兹曼研究

Systematic Evaluation of Stencil Configuration, Forcing Scheme, and Resolution Effects in the Stratified Taylor--Green Vortex: A Lattice Boltzmann Study

本文系统评估了格子玻尔兹曼方法在三维分层格林涡中的预测能力，探讨了 stencil 配置、强迫方案和分辨率的影响，发现 D3Q27×19 配置在精度和效率之间取得最佳平衡，且需至少 256³ 分辨率以实现定量收敛。

On the internal gravity waves in the stratified ocean with shear flows

In this paper, we consider a fundamental problem of describing the dynamics of internal gravity waves in the stratified ocean with shear flows. We develop an asymptotic representation of the wave fields in terms of the Green's functions. We explore the far field of the internal gravity waves generated by disturbing sources, and propose asymptotic algorithms for calculating its dynamics.

Stratified Radiative Transfer for Multidimensional Fluids

New mathematical and numerical results are given for the coupling of the temperature equation of a fluid with Radiative Transfer: existence and uniqueness and a convergent monotone numerical scheme. The technique is shown to be feasible for studying the temperature of lake Leman heated by the sun and for the earth atmosphere to study the effects of greenhouse gases.

Generation of turbulence through frontogenesis in sheared stratified flows

The large-scale structures in the ocean and the atmosphere are in geostrophic balance, and a conduit must be found to channel the energy to the small scales where it can be dissipated. In turbulence this takes the form of an energy cascade, whereas one possible mechanism in a balanced flow at large scales is through the formation of fronts, a common occurrence in geophysical dynamics. We show in this paper that an iconic configuration in laboratory and numerical experiments for the study of turbulence, that of the Taylor-Green or von Kármán swirling flow, can be suitably adapted to the case of…