S. G. Ganga Prasath, Rama Govindarajan and Vishal Vasan’s recently published paper titled ‘Accurate solution method for the Maxey-Riley equation, and the effects of Basset history’ in the Journal of Fluid Mechanics, has been chosen to be featured in ‘Focus on Fluids’. Focus on Fluids is a monthly feature of the Journal of Fluid Mechanics, and highlights publications that have made significant contributions to the field of fluid mechanics.
The dynamics of spherical particles in a viscous fluid is governed by the well-accepted Maxey–Riley equation at small Reynolds number. This equation represents Newton’s second law, equating the rate of change of the linear momentum with all forces acting on the particle. One of these forces, the Basset–Boussinesq memory term, however, is notoriously difficult to handle, which prompts most studies to ignore this term despite ample numerical and experimental evidence of its significance. The key idea of the paper is a novel reformulation of the Maxey-Riley equation that completely eliminates all the difficulty of handling the Basset-Boussinesq term. One of the main findings is that the Basset-Boussinesq term, which is usually thought to be a drag force, can under particular circumstances even accelerate the particle.
The article, by George Haller (ETH, Zurich), explaining the significance of this work, can be downloaded here.