(6f) Visulization of Transport Dynamics in Complex Fluids

Authors: 
Mohammadigoushki, H., UC Berkeley

2nd year Post-doctoral Fellow:

Research Interests:

Complex fluids are ubiquitous in nature and the industry.  Interesting behaviors arise from these fluids in ways that are difficult to predict directly from their single constituents. This sometimes makes complex fluids useful in some processes that simple materials cannot be used for. It is clear that the complex nature of these fluids is directly connected to their microstructure . Moreover, experimental observations of transport processes in these systems help to elucidate the microscopic nature of their complex behavior. This in turn enables us to tailor the properties of complex fluids for a specific target function.  For example, visualization of flow of liquid foams in simple geometries reveals how the interaction between microscopic constituents (i.e. bubbles) affect the macroscopic behavior of material. In another example, simple visualization of the transport of a solid object in a shear banding polymeric fluid reveals how strong and/or flexible the polymer chains are. 

Proposals: NSERC Discovery Grant, Canadian Foundation for Innovation, National Science Foundation and American Chemical Society-Petroleum Research Fund.

Postdoctoral Project: "Instability of Shear Banding Fluids in Taylor-Couette Geometry"

Under supervision of Susan J. Muller , Chemical and Biomolecular Engineering, University of California, Berkeley.

PhD Dissertation: "Dynamics and Rheology of Sheared Liquid Foams".

Under supervision of James J. Feng, Chemical and Biological Engineering, University of British Columbia.

Research Experience:

Over the past few years, I have been investigating few projects from both engineering and scientific perspectives. I have been formally trained as chemical engineer with specialty in transport processes in complex systems such as Liquid foams, Viscoelastic, and shear banding fluids. My approach to tackle these pressing problems is mostly through experimentation. Moreover, I have extended my knowledge and expertise by collaborating with multi-disciplinary team of engineers and scientists at UBC and UC Berkeley on couple of transport projects in micro-fluidic devices. As a result of my training and collaborations, I have been proficient in designing, and developing new methods to study the complex behavior and gained a deep understanding of the physics of these systems by directly visualizing their transport process. This in turn greatly helped illuminating the nature of the complex interactions between microscopic elements of these materials which serves as a crucial step to design a smart material or process.         

Teaching Experience:

Teaching is an important component of the academic profession. I strongly believe that teaching and research go hand-in-hand. I am committed to the teaching as evidenced from my teaching experiences. I have been teaching assistant for multiple courses in Faculty of Applied Science at University of British Columbia and often taught the course materials as guest instructor. I have instructed undergraduate students in variety of chemical engineering courses such as, Transport Phenomena, Thermodynamics and also in Numerical Computations for Engineering and Science. In addition, I have supervised two senior undergraduate students at UC Berkeley for their projects. My main interest lies in teaching of transport phenomena that includes heat, mass and momentum transfer as well as Thermodynamics. I am well experienced in teaching thermo-fluids for undergraduate students. During my teaching experience at UBC, I realized that teaching is very rewarding to me. This led me to take an intense teaching course offered by learning and education centre at UBC. In this course, I was instructed by well known world class teachers on several teaching techniques. Those techniques were adapted to scientific courses at the university level, and at the end of program I was issued a teaching certificate from UBC teaching and learning centre.

Vision for Future direction:

As a faculty member, I would like to continue applying my experimentations and analytical skills in studying the complex fluids that are applicable in areas from biotechnology to food, and oil-gas industries. My overall approach is to make the investigation of these systems more tractable by using simple and well-developed devices.  This will be accomplished by fabricating simple devices and incorporating several techniques such as, particle image velocimetry, and viscometry in experiments. I would also like to continue collaborating with scientist from all other related fields which will at the end, bring a solid and concrete understanding of the nature of the complex behavior.

Selected Publications and Submissions:

  • Mohammadigoushki, H., and Muller, S. J., " Interface dynamics in a wormlike micellar fluid sheared in a Taylor-Couette cell: A study on interface travel " Submitted to Soft Matter, (2015).
  • Mohammadigoushki, H., and Feng, J. J., "Temporal evolution of microstructure and rheology of sheared two-dimensional foam" J. Non-Newtonian Fluid Mech. 223, 1-8 (2015).
  • Mohammadigoushki, H., Yue, P. and Feng, J. J., "Bubble migration in two-dimensional foam sheared in a wide-gap Couette device: effects of non-Newtonian rheology".  J. Rheol. 58, 1809-1827 (2014).
  • Mohammadigoushki, H and Feng, J. J., "Size segregation in sheared two-dimensional polydisperse  foam." Langmuir 29, 1370-1378 (2013).
  • Mohammadigoushki, H. & Feng, J. J., "Size-differentiated lateral migration of bubbles in Couette flow of two-dimensional foam". Phys. Rev. Lett. 109, 084502 (2012).