Mohsen Eshraghi

Large‐Scale Simulation of Dendritic Solidification

A new computational approach based on the lattice Boltzmann and the cellular automaton methods is developed with the objective of simulating the growth of dendritic structures of metallic alloys under convection. The tracking of the solid-liquid interface is performed with a cellular automaton algorithm, while the solution of the flow equations, solute, and energy transport is done with the lattice Boltzmann method. Both methods are characterized by a local-type nature, requiring no assembly and solution of global equations. This feature enables efficient scaling of the model in petaflops supercomputers, allowing the simulation of large domains containing thousands of dendrites. The model capabilities with simulations of a binary alloy are discussed and the parallel performance of the algorithm is assessed. Excellent strong scaling up to thousands of computing cores is obtained across the nodes of a computer cluster, along with near-perfect weak scaling.

Development of an ocean-themed introduction to engineering & technology course for freshmen students

The paper provides an overview of the development of a new Introduction to Engineering and Technology course for freshmen students. The course provides an opportunity to introduce engineering students early on to the field of ocean engineering and opportunities in the Navy STEM field. The course relies heavily on a hands-on laboratory component that builds on technical content introduced in the lecture. The centerpiece of the class is the design and build of a mini-ROV by student teams. The results of a survey indicate that the ROV activity had the highest impact on increasing student understanding of what it means to be an engineer or technologist. More than three quarters of the students indicated that they were interested in considering ocean engineering/technology career opportunities. Almost half of the students indicated that they were interested or very interested in considering career opportunities in a Naval STEM field.

A Lattice Boltzmann Model for Dendritic Growth under Natural Convection

A two-dimensional (2D) lattice Boltzmann (LB) and Cellular Automaton (CA) model is developed to study the buoyancy-induced flow pattern during equiaxed and columnar dendritic solidification in a binary alloy. The complex flow pattern during solidification has a significant influence on redistribution of solute and heat. In the present work, lattice Boltzmann method (LBM) is used to solve for solute diffusion, heat transfer and fluid flow, while CA is employed to capture the solidification interface. The results show that natural convection has a significant effect on morphology of both columnar and equiaxed dendrites.