带非线性阻尼的欧拉方程组正规解的爆破
2016-12-27朱旭生傅春燕赵康鑫
朱旭生,傅春燕,赵康鑫,王 莉
(华东交通大学理学院,江西 南昌330013)
带非线性阻尼的欧拉方程组正规解的爆破
朱旭生,傅春燕,赵康鑫,王 莉
(华东交通大学理学院,江西 南昌330013)
研究了n(n≥1)维空间理想可压缩流中带有非线性阻尼项的等熵欧拉方程组的初值问题。当初始密度有紧支集时,利用泛函结合特征线的方法,证明了在真空情形下带有形如-αρ|u|θu阻尼项的可压缩等熵欧拉方程组,其阻尼系数α为正常数时的正规解在初始数据一定大时必定爆破,其中0<θ<1。
等熵欧拉方程组;泛函方法;爆破
考虑下列n(n≥1)维空间中带阻尼项的等熵欧拉方程组:
的Cauchy问题.其初始条件为
其中:ρ,u,p分别表示气体的密度,速度和压力;状态方程为p=Aργ(A>0);γ为绝热指数(γ>1);其中常数α>0;0<θ<1。
对带阻尼项的欧拉方程组的研究有很多成果,大多是研究ρ>0的情形,当初值是在一个扩散波或者常状态的平衡解附近的小扰动,经典解整体存在详情参见[1-3];但关于欧拉方程组的爆破也有大量的研究,例如[4-11]。文献[4-6]研究了初值具有紧支集的情形,证明了某些情况下正规解会在有限时间内爆破;文献[7]研究三维空间的可压缩流的非等熵欧拉方程组的奇性的形成;文献[8-9]研究等熵欧拉方程组初边值问题的轴对称解的爆破;文献[10]考察运用泛函方法证明一维空间中带非线性阻尼项的等熵欧拉方程组在初始密度有紧支集时正规解的爆破;文献[11]研究了阻尼系数为常数的欧拉方程组和带退化阻尼的等熵欧拉方程组,得到了在初始密度有紧支集时,正规解都将在有限时间内爆破。本文在文献[4,8,10,11]的基础上运用泛函结合特征线的方法考察了带有如阻尼的欧拉方程组的情形,其中0<θ<1。而当θ=1时的情形在文献[10]已有详细证明。
1 主要定理及其证明
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Blowup of the Regular Solutions of the Euler Equations with Nonlinear Damping
Zhu Xusheng,Fu Chunyan,Zhao Kangxin
(School of Science,East China Jiaotong University,Nanchang 330013,China)
The regular solutions of then-dimensional isentropic Euler equations with the nonlinear damping for a perfect gas are investigated in this paper.Utilizing the methods of the functional in combination with characteristics,we prove the compressible isentropic Euler equations in vacuum case with the damp like-αρ|u|θu.If its damping coefficientαis positive constant when the initial data are large enough the regular solutions would blow up in finite time.
isentropic Euler equation;functional methods;blowup
O175.4
A
1005-0523(2016)06-0137-06
(责任编辑 刘棉玲)
2016-02-28
国家自然科学基金项目(11161021,11561024);江西省自然科学基金项目(20151BAB201017)
朱旭生(1968—),男,副教授,博士,研究方向为偏微分方程。