Rotational Kinematics of Finite-Sized Cylinders in Turbulence

Date: 
Friday, March 10, 2017 - 2:30pm
Location: 
3110 Etcheverry Hall
Speaker: 
Dr. Ankur Bordoloi

Post-Doc Fellow, Extreme Fluids Group

Los Alamos National Laboratory, NM

About: 

E-201 Ocean Engineering Seminar Series, Spring 2017

 

2:00 - 2:30pm Beverages & Refreshments

2:30 - 4:00pm Seminar

 

Particles smaller than the Kolmogorov scale have been a focus of numerous numerical studies in the past few decades. Since they are in the Stokes flow regime, these particles can be treated as tracers and modeled in a straightforward way using creeping flow equations. By contrast, particles whose size is larger than the Kolmogorov scale interact with turbulence in a much more complex way. Due to their size, these particles experience non-linear velocity gradients of the carrier fluid; the tracer assumption vanishes and analytical equations can no longer predict their dynamics accurately. In this talk, I will present experimental results examining rotational kinematics of finite-sized cylinders in homogenous isotropic turbulence, focusing on the effects of particle size and shape. It will be shown that the mean particle enstrophy follows a -4/3 power-law scaling with respect to the volume-equivalent spherical diameter of the particle, irrespective of particle-shape. Methodology on decomposition of particle rotation rate into spinning and tumbling will be presented, with results showing equi-partition of enstrophy about each of the particles’ local axes.

 

Biography:

Ankur Bordoloi is a postdoctoral scholar in the Physics division at Los Alamos National Laboratory (LANL). Ankur received his PhD (2014) in Aerospace Engineering & Mechanics at University of Minnesota and an MTech (2009) in Mechanical Engineering at Indian Institute of Technology, Kanpur. After his PhD, he worked for a year as a postdoctoral scholar with Prof Evan Variano in the Civil and Environmental Engineering department at University of California, Berkeley. His primary research interest is in experimental fluid mechanics in the realms of droplet dynamics (coalescence, wetting, etc), particle turbulence interactions, and shock-wave driven flows. In this seminar, he will present some of his work at Prof Variano's lab investigating particle's kinematic response to turbulence that has implications related to the locomotion of some marine organisms.

 

­­Hosted by: Prof. Evan Variano (variano@berkeley.edu)