提取全波列声波测井信号波前的一种新方法

把平滑过渡信号作为全波列声波测井信号中的各种波的数学模型,研究了其连续子波变换的波形特点,提出了一种提取其起始点的新方法.利用此方法可以精确地提取全波列声波测井信号的滑行纵波、滑行横波及斯通利波的波前.     

Tailing wavetrain generation in precursor soliton generation in single-layer flow

A theory of tailing wavetrain generation in the precursor soliton generation in single-layer flow is presented in terms of Whitham s averaged method in the present paper. The group characters of the tailing wavetrain generation are represented by the evolution equations of roots of a cubic algebraic equation resulting from the fKdV equation in the single-layer flow without source term. Based on the evolution equations, the group velocity of the tailing wavetrain is found theoretically, furthermore a theoretical solution of the tailing wavetrain generation is found in terms of the evolution equations. To examine the theoretical results, a numerical calculation of fKdV equation in single-layer flow is carried out in the laboratory frame, at the same time a comparison is also done. The comparison between theoretical and numerical results shows they are in good agreement.