The partial differential equations (PDEs) group here at OSU focuses on the analysis and applications of several nonlinear PDEs, especially those arising in fluid mechanics, geophysics, astrophysics, meteorology and other science and engineering practice. The particular PDEs that the faculty members here have worked on include the Navier-Stokes equations, the surface quasi-geostrophic equations, the Boussinesq equations, the magnetohydrodynamics equations and other related equations. These PDEs have been at the center of numerous analytical, experimental, and numerical investigations. One of the most fundamental problems concerning these PDEs is whether their solutions are globally regular or they develop singularities in a finite-time. The regularity problem can be extremely difficult, as in the case of the 3D Navier-Stokes equations. The global regularity problem on the 3D Navier-Stokes equations is one of the Millennium Prize Problems. In addition, the PDEs group here is also interested in the numerical computations and analysis of the aforementioned PDEs.