Title: The uniform time of existence of the smooth solution for 3D Euler-$α$ equations with Dirichlet boundary conditions
Abstract: After reformulate the incompressible Euler-$α$ equations in 3D smooth domain with Drichlet data, we obtain the unique classical solutions to Euler-$α$ equations exist in uniform time interval independent of $α$. We also show the solution of the Euler-$α$ converge to the corresponding solution of Euler equation in $L^2$ in space, uniformly in time. In the sequel, it follows that the $H^s$ $(s>\frac{n}{2}+1)$ solutions of Euler-$α$ equations exist in any fixed sub-interval of the maximum existent interval for the Euler equations provided that initial is regular enough and $α$ is small sufficiently.