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arXiv 2302.05112math.AP
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奇异极限下分数阶高阶非线性声学方程

Nonlinear acoustic equations of fractional higher order at the singular limit

Vanja Nikolić

AI总结:

本文研究具有反常扩散介质中分数阶高阶非线性声学方程在松弛时间趋于零时的奇异极限,证明其可近似为 Westervelt、Blackstock 或 Kuznetsov 方程,并通过针对弱奇异记忆核强制性设计的检验方法获得解的一致有界性。

摘要:

当高频声波在具有反常扩散的介质(如生物组织)中传播时,其运动可由分数阶高阶非线性波动方程描述。这些方程可理解为非线性声学中 Jordan-Moore-Gibson-Thompson 方程的非局部推广。本文将它们与经典二阶声学方程联系起来,并在此意义上论证它们在较小松弛时间下作为经典方程近似的合理性。为此,我们对一类相应的非局部波动模型进行奇异极限分析,并确定其在松弛时间趋于零时的行为。我们证明,根据非线性项的不同以及对数据所作的假设,这些模型可视为 Westervelt、Blackstock 或 Kuznetsov 波动方程的近似。该分析依赖于含分数阶高阶导数方程解的一致有界性,这些界通过一种针对所涉(弱)奇异记忆核的强制性性质而设计的检验方法获得。

英文摘要:

When high-frequency sound waves travel through media with anomalous diffusion, such as biological tissues, their motion can be described by nonlinear wave equations of fractional higher order. These can be understood as nonlocal generalizations of the Jordan-Moore-Gibson-Thompson equations in nonlinear acoustics. In this work, we relate them to the classical second-order acoustic equations and, in this sense, justify them as their approximations for small relaxation times. To this end, we perform the singular limit analysis for a class of corresponding nonlocal wave models and determine their behavior as the relaxation time tends to zero. We show that, depending on the nonlinearities and assumptions on the data, these models can be seen as approximations of the Westervelt, Blackstock, or Kuznetsov wave equations. The analysis rests upon the uniform bounds for the solutions of the equations with fractional higher-order derivatives, obtained through a testing procedure tailored to the coercivity property of the involved (weakly) singular memory kernels.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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