9. Vorticity-related problems¶ Summary Subject: Drag, lift and history forces in relation with vorticity Key idea Vorticity \(\nabla \times \mathbf{v}\) plays key roles in hydrodynamic forces acting on particles. References: Stone [Sto93] Legendre [Leg07] Auton [Aut87] Landau and Lifshitz [LL87] 9.1. Drag acting on a solid sphere in Stokes flow (GKB) 9.2. Drag-enstrophy relation 9.3. Drag-vorticity relation 9.4. Lift acting on spherical body in inviscid flow with weak shear 9.5. Basset (history) force on a solid sphere in Stokes flow