频率域2.5维电磁测深有限元模拟中的吸收边界条件

Absorbing boundary condition for simulating 2.5-D electromagnetic sounding in frequency domain by finite element method

针对频率域2.5维电磁测深问题,借鉴地震波模拟中吸收边界的处理方法,将波数域电磁场方程分解成两个传播方向相反的单程波方程,以沿边界外法向衰减的单程波方程作为该边界上的吸收边界条件。给出了全吸收边界条件的构造方法,并导出了15°吸收边界的具体形式。数值计算结果表明,该吸收边界条件使边界反射得到了有效压制,在相同的计算量下计算精度显著提高。

Referring to the method of constructing absorbing boundary condition in seismic wave modeling, absorbing boundary condition for simulating 2. 5-D electromagnetic sounding in frequency domain was studied by finite element method. Electromagnetic equation was decomposed into two reverse direction one-way wave equations in .wavenumber domain. Then, the one-way equation, which decayed along the outer normal direction was treated as the absorbing boundary condition of that boundary. The method how to construct full absorbing boundary condition was given, and 15° absorbing boundary condition was formulated. Numerical results indicate that this boundary condition effectively suppresses reflection and improves solution accuracy remarkably.