Welcome to my website!

I am Sreeram Rajesh, a mechanical engineering PhD student at UC Santa Barbara. I am quite interested in the capillary flows of complex fluids such as polymer solutions, and particulate suspensions, which I study using model experiments involving droplets, liquid bridges, and bubbles. Microdroplets of such complex fluids are often encountered in inkjet and 3D printing. The rheology of such capillary flows is also essential to decipher the role of cohesion in the flow of granular materials, for instance during beach erosion, or microplastic transport. Particulate flows are also industrially relevant to control the preparation of good quality slurries of lithium-ion or silver pastes used in solar panels.

Education

Ph.D. in Mechanical Engineering

University of California, Santa Barbara since September 2020. 

Capillary interaction of particles in complex fluids
Supervisor: Alban Sauret

My doctoral research investigates the capillary flows of complex fluids and their role in controlling the flow of cohesive granular materials. I use experimental techniques such as high-speed video microscopy to characterize the microrheology of the complex fluids, and granular collapse experiments to link the microrheology to the macroscopic cohesion.

B.E. in Manufacturing Engineering

Birla Institute of Technology and Science, Pilani from 2015-2019

Dissertation: Millifluidic device for measuring bacterial growth in space
Supervisor: Aloke Kumar (IISc), K.R.C. Murthy

As an undergraduate, I worked on projects involving Computer-Aided Design, Computational Fluid Mechanics, finite element analysis, and additive manufacturing. I got the opportunity to work at the Indian Institute of Science for my undergraduate dissertation, where I designed a millifluidic device for an Astrobiological experiment in collaboration with the Indian Space Research Organization.

Microplastic Transport

Settling dynamics biopolymer-laden microplastics

Axial liquid bridges

Capillary rheology of a liquid bridge of polymer solution between two spherical particles

Pinch-off of fibers

Break up dynamics of suspensions of fibers

Cohesive Cliff Collapse

Influence of inter particle cohesion on the collapse of granular structures

My Skill Sets

Laboratory and Workshop

  • Design of Experiments
  • High-Speed Imaging- Using phantom VEO 710 and VEO 600 at frame rates of 1000-500000 per second. 
  • Wet Lab- water, glycerol, and silicone oil solvents to prepare polyethylene oxide polymer solutions, microparticulate and fiber suspensions. 
  • Laser Cutting (Trotec Speedy 100) of acrylic sheets for experiments.
  • 3D Printing using FDM and SLA printers.
  • Rheometry- Viscosity, shear and normal stress, storage and loss modulus measurement for polymer solutions and suspensions, develop custom routines for fitting various rheological models.
  • Solidworks, Fusion360- Build 3D models for experimental design and simulations, rendering for visualization, and 3D printing custom parts.
 Scientific Programming
  • Python, ImageJ, Matlab – Develop custom macros and routines for image analysis, data extraction, fitting, and publication quality plots. Write finite difference schemes for CFD.
  • Ansys, Comsol, OpenFOAM - Setup CFD simulations of channel flow in microfluidic devices, turbulent flow around solid structures.
  • Arduino- Setting up circuits and measuring data from load cells (Futek LSB200), humidity sensor (Honeywell 4000 series), photodiode (OPT 101), Strain gauge amplifiers, and data acquisition systems (Labjack U6).

Past Projects

Abrasive slurry-based polishing | IISc, 2019-2020
Project Assistant

I developed analytical and numerical models of a yield-stress fluid to characterize its abrasive properties. The fluid is embedded with abrasive particles, and polishing is achieved by abrasive erosion of the surface. 

Hyperloop India | BITS Pilani, 2016-2017
Logistics Lead, Aerodynamic Engineer

Hyperloop India was one of the 24 teams from across the world, and the only Indian team to make it to the finals of the 2017 SpaceX Hyperloop competition. Hyperloop India was also one of the seven winners of the Hyperloop One Global Challenge, a case study report challenge. We designed and manufactured a prototype Hyperloop pod, which we presented at the competition finals in Hawthorne, CA. Intrigued? Read more about our story here.

Prosthesis rapid prototyping | BITS Pilani, 2018-2019
Design Intern

I worked for a start-up, PSPR 3D tech, that designs and manufactures affordable 3D prosthetic structures. Part of my work was to develop CAD models from patient data and perform a structural analysis of the model. Here is a link to my published work.

Interested in my work?
You can reach me at sreeram[at]ucsb.edu