On the slow motion of a sphere in fluids with non-constant viscosities

Bong Jae Chung, Ashwin Vaidya

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We study a slowly moving sphere in fluids where the viscosity depends upon factors such as shear-rate, temperature and pressure, with the flow field approximated by the Stokes flow past a sphere. We derive an expression for the stresses generated in the fluid due to these various factors. This gives us information about both, the force imposed by the fluid upon the sphere and also the reaction force due to the sphere upon the fluid, referred to as the stress density. The values of the force and stress density are numerically computed in each of the cases and analyzed for various values of the flow and material parameters. Our computations show interesting variations in the distribution of stress density in the fluid for the various cases and also give us valuable information about the effect of walls. Our calculations also indicate that particle heating or cooling can serve as a significant control parameter since the drag force upon the sphere increases dramatically for a cold particle and can be reduced considerably upon heating it.

Original languageEnglish
Pages (from-to)78-100
Number of pages23
JournalInternational Journal of Engineering Science
Issue number1
StatePublished - Jan 2010


  • Drag reduction
  • Hot particle
  • Power-law fluid
  • Pressure dependent viscosity


Dive into the research topics of 'On the slow motion of a sphere in fluids with non-constant viscosities'. Together they form a unique fingerprint.

Cite this