Global solutions to the Oldroyd-B model with a class of large initial data

Consider a global wellposed problem for the incompressible Oldroyd-B model. It is shown that this set of equations admits a unique global solution provided the initial horizontal velocity $u^h_0$, the product $\om u^d_0$ of the coupling parameter $\om$ and initial the vertical velocity $u^d_0$, and initial symmetric tensor of constrains $\tau_0$ are sufficient small in the scaling invariant Besov space $\dot{B}^{\fr{d}{2}-1}_{2,1}\times\dot{B}^{\fr{d}{2}}_{2,1}, d\ge2$. In particular, the result implies the global well-posedness of Oldroyd-B model with large initial vertical velocity $u_0^d$.