A free boundary inviscid model of flow-structure interaction
Mustafa Sencer Aydın, Igor Kukavica, Amjad Tuffaha
TL;DR
The paper studies local-in-time well-posedness for the 3D incompressible Euler equations coupled with an Euler–Bernoulli plate via a free boundary, in a channel geometry. It fixes the moving domain using an Arbitrary Lagrangian–Eulerian (ALE) transformation, producing a variable-coefficient Euler system with pressure $q$ and a plate equation $w_{tt}+\Delta_{h}^{2} w-\nu \Delta_{h} w_t = q$ on the interface, along with compatibility and zero-average pressure conditions. It proves local existence and uniqueness of strong solutions with minimal Sobolev regularity: initial fluid velocity in $H^{2.5+\delta}$ and plate velocity in $H^{1+\delta}$ (for any $\delta\in(0,1/2]$), yielding $v\in L^{\infty}([0,T];H^{2.5+\delta})$, $q\in L^{\infty}([0,T];H^{1.5+\delta})$, $w\in L^{\infty}([0,T];H^{4+\delta})$, and $w_t\in L^{\infty}([0,T];H^{2+\delta})$. The proof combines pressure elliptic estimates, tangential energy arguments, and vorticity bounds within a continuation framework, and establishes uniqueness via a Gronwall-type estimate for the solution differences. This advances the mathematical understanding of inviscid fluid–structure interaction with free boundaries by providing robust local well-posedness under minimal regularity assumptions.
Abstract
We address the existence and of solutions for the Euler-plate free-boundary system modeling an interaction of a three-dimensional inviscid fluid and an evolving plate. We prove the local existence and uniqueness of solutions for initial fluid and structural velocities belonging to $H^{2.5+}$ and $H^{2+}$, respectively. The results justify earlier a~priori estimates shown by two of the authors.
