摘要
提出一种等价的一阶双曲型速度-应力Biot双相各向同性介质弹性波波动方程,以实现双相介质混合波场中纯快慢纵波和纯横波波场分离的问题.应用散度和旋度理论证明双相介质等价方程波场分离的可行性,采用高阶交错网格有限差分法构建高精度正演算子,推导其PML吸收边界条件和稳定性条件,并对均匀双相介质和层状非均匀双相介质模型进行数值模拟试验,准确得到固流相混合弹性波场、被完全分离的纯纵横波波场,同时边界吸收效果良好,数值模拟精度较高.计算结果还表明,固流相中的快慢纵波相互伴生因而无法实现分离,且归属于纯纵波波场,流相慢纵波能量比固相慢纵波能量强,这对认识双相介质弹性波的传播规律以及完善双相介质理论具有重要意义.
We propose an equivalent first-order hyperbolic velocity-stress Biot two-phase isotropic medium elastic wave equation in order to separate pure fast and slow compress waves and pure shear wave in full wave field of two-phase medium.Feasibility of the method is demonstrated with divergence and curl theory.In a high-order staggered-grid finite-difference scheme forward simulating operator is constructed.PML absorbing boundary condition and stability condition are derived.Isotropic and heterogeneous layered two-phase medium models are tested.Full elastic wave field,completely separated pure compress wave and pure shear wave of the solid fluid phase components are obtained.Boundary absorbing effect is perfect,and numerical precision is high.It shows that the fast compress wave and slow compress wave are coupled which can＇t be separated.They belong to pure compress wave fields.Energy of slow compress wave in fluid phase is greater than that in solid phase which is important in understanding propagating laws and validating elastic wave theory for two-phase medium.
出处
《计算物理》
EI
CSCD
北大核心
2011年第3期404-412,共9页
Chinese Journal of Computational Physics
关键词
Biot双相各向同性介质
等效波场分离数值模拟方程
纯快慢纵波和纯横波
PML吸收边界条件
固相和流相
Biot two-phase isotropic medium
equivalent wave field separation numerical simulation equation
pure fast ＆ low p wave and s wave
PML absorbing boundary condition
solid phase and fluid phase
