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arXiv · 2610.39204

The small Deborah number limit for the fluid-particle flows: incompressible case

Zhendong Fang·Kunlun Qi·Huanyao Wen
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Abstract

This work is devoted to the study of the hydrodynamic limit for the fluid-particle flows governed by the Vlasov-Fokker-Planck (VFP) equation coupled with the incompressible Navier-Stokes (INS) equation as the Deborah number approaches to zero. The limit is valid globally in time provided that the initial perturbation is small in a neighborhood of a steady state. The proof is based on a formal derivation of the limiting system via the Hilbert approach, followed by a rigorous justification via introducing a novel decomposition involving some macroscopic quantities and a refined energy estimate motivated by macro-micro decomposition. In contrast to the existing results for the same scaled model, the present work provides the first one on the hydrodynamic limits in a strong sense with an explicit convergence rate.

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Zhendong Fang, Kunlun Qi, Huanyao Wen. 2026-10-29. The small Deborah number limit for the fluid-particle flows: incompressible case. https://doi.org/10.1142/s0218202524500489

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