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arXiv 2610.13613math.AP
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半空间中三维趋化性-纳维-斯托克斯系统的整体存在性与部分正则性

Global Existence and Partial Regularity for the Three-Dimensional Chemotaxis--Navier--Stokes System in a Half-Space

School of Mathematical Sciences, Dalian University of Technology(大连理工大学数学科学学院)

Yubo Chen, Jianbo Yu

AI总结:

该研究针对半空间中三维趋化性-纳维-斯托克斯系统,建立了合适弱解的端点部分正则性,构造了无初始数据小性限制的整体弱解,并得到了解的渐近行为等结果。

摘要:

我们在无滑移和无通量边界条件下,针对半空间中具有恒定灵敏度和线性消耗的三维趋化性-纳维-斯托克斯系统的合适弱解,建立了端点部分正则性结果。整个时空奇异集(包括其边界部分)的一维抛物豪斯多夫测度为零。该结果基于自然r⁻¹耗散尺度下的Caffarelli-Kohn-Nirenberg型准则,该准则在内部点和边界点均有效,无需额外的压力小性条件。关键估计将加权质量控制与局部化熵-能量不等式相结合,以在不引入单独的n log n项的情况下完成迭代,并考虑了重标度产生的质量项。与边界兼容的压力和热分解可得到局部赫尔德正则性。我们还证明了一个低阶准则,该准则仅要求速度、信号梯度和压力振荡的小性,其阈值取决于任意有限的密度质量界。在自然熵和能量假设下,我们构造了合适的整体弱解,对初始数据无小性限制。势函数是时间无关的,具有有界梯度;仅在长时间结果中假设势函数本身有界。若其梯度也是赫尔德连续的,则可选取一个解,使其在有限等待时间后在整个闭半空间中变为有界且经典解。对于该解,我们在无初始空间矩假设的情况下,获得了两个标量分量的衰减和诺依曼高斯渐近行为。其剖面系数分别为守恒的细菌质量和极限信号质量,当初始信号非零时,后者严格为正。

英文摘要:

We establish endpoint partial regularity for suitable weak solutions to the three-dimensional chemotaxis--Navier--Stokes system with constant sensitivity and linear consumption in a half-space under no-slip and no-flux boundary conditions. The full space--time singular set, including its boundary part, has vanishing one-dimensional parabolic Hausdorff measure. This follows from a Caffarelli--Kohn--Nirenberg type criterion at the natural $r^{-1}$ dissipation scaling, valid at interior and boundary points without additional pressure smallness. The key estimate combines weighted mass control with the localized entropy--energy inequality to close the iteration without a separate $n\log n$ quantity and accounts for the mass term generated by rescaling. Boundary-compatible pressure and caloric decompositions yield local Hölder regularity. We also prove a lower-order criterion requiring smallness only of the velocity, signal gradient, and pressure oscillation, with a threshold depending on an arbitrary finite density mass bound. We construct global suitable weak solutions under natural entropy and energy assumptions without smallness restrictions on the initial data. The potential is time-independent with bounded gradient; boundedness of the potential itself is assumed only for the large-time results. If its gradient is also Hölder continuous, a solution can be selected to become bounded and classical throughout the closed half-space after a finite waiting time. For the same solution, we obtain decay and Neumann Gaussian asymptotics for both scalar components without initial spatial moment assumptions. The profile coefficients are the conserved bacterial mass and the limiting signal mass, respectively, and the latter is strictly positive whenever the initial signal is nonzero.

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