Ehsan Madadi-Kandjani

California State University, Long Beach | CSULB · Department of Mechanical & Aerospace Engineering

The SWMM5+ project began with the observation that the EPA SWMM hydraulic solver: (i) is the primary consumer of computational time, (ii) is the source of model instability/mass non-conservation, (iii) limits parallelization, and (iv) cannot support mass-conservative Advection-Diffusion-Reaction (ADR) transport modeling. The new SWMM5+ solver provi...

Confined Impinging Jet Mixers (CIJMs) are widely used due to their small-scale-mixing efficiency. This property makes them especially useful for nanoprecipitation. The CIJM process parameters are computationally expensive to predict when using direct-numerical simulation (DNS) and large-eddy simulation (LES). In this work, binary nonreactive mixing...

A solid fuel ramjet has been recognized as a viable contender for atmospheric supersonic flight due to its performance and simple construction. However, the static temperature increases due to shock compression at the inlet that results in high temperature air entering the combustor. As such, the goal of this study is to analyze how the kinetics an...

Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advance...

This work presents a vision of future water resources hydrodynamics codes that can fully utilize the strengths of modern high-performance computing. The advances to computing power, formerly driven by the improvement of central processing unit processors, now focus on parallel computing and, in particular, the use of graphics processing units (GPUs...

This poster presents preliminary efforts from the NCIMM group at UT Austin to improve the computing speed of an explicit-solving version of the SWMM engine through the use of intelligent partitioning. The outline for a novel heuristic partitioning scheme is included.

This work describes the development of a plugin in the new SWMM-EPANET User Interface (UI) environment. The plugin package solves the well-studied least-cost design problem of water distribution systems, implementing genetic algorithms as the optimization approach. Simulation of water distribution systems is crucial for the technical planning and m...

The extended quadrature method of moments (EQMOM) for the solution of population balance equations (PBE) is implemented in the open-source computational fluid dynamic (CFD) toolbox OpenFOAM as part of the OpenQBMM project. The moment inversion procedure was designed (Nguyen et al., 2016) to maximize the number of conserved moments in the transporte...

An extended quadrature method of moments using the β kernel density function (β-EQMOM) is used to approximate solutions to the evolution equation for univariate and bivariate composition probability distribution functions (PDFs) of a passive scalar for binary and ternary mixing. The key element of interest is the molecular mixing term, which is des...

A conditional quadrature method of moments (CQMOM) was developed to solve turbulent mixing problems associated with population balance equations (PBE) by approximating the evolution equation of the composition probability density function (PDF) for the moments of the PBE. The well-established Interaction-by-Exchange-with-the-Mean (IEM) model was us...

One of the important attractions of employing the transported probability density function (PDF) methods for turbulent reacting flows is the fact that the chemical source terms are treated exactly. The composition probability density function (PDF) evolves with convective transport in physical space due to the mean velocity (macromixing), the turbu...

Computational fluid dynamics (CFD) modeling of turbulent reacting flows has a variety of applications, including minimizing the amount of pollutants from internal combustion engines and maximizing the selectivity of a desired product in a chemical reactor. One goal of modeling these flows is to better understand how fluid mixing affects selectivity...

An extended quadrature method of moments (EQMOM) with log-normal kernel density functions is developed in this work, and applied to the solution of a population balance equation (PBE) for aggregation and breakup, coalescence, and condensation problems. The cases with one and two kernel density functions are studied analytically, and the existence o...

The evolution of the particle size distribution in polydisperse systems is regulated by the population balance equation (PBE) [1]. A successful approach to solve the PBE is the quadrature method of moments (QMOM), in which the particle size distribution is approximated by a discrete number of Dirac delta functions uniquely determined from a truncat...

A numerical study was conducted to investigate the validity of using the spring-backed membrane model for compliant walls (CWs), and to explain the failure of the reference study [Duncan and Zhang, Journal of Fluid Mechanics 1991, (226) 401-423] to reproduce the bubble behavior near moderately elastic CWs. The same mathematical models used in the r...

The lattice Boltzmann method (LBM) for simulating fluid phases was coupled with the discrete element method (DEM) for studying solid phases to formulate a novel solver for fast discrete particle simulation (DPS) of particle-fluid flows. The fluid hydrodynamics was obtained by solving LBM equations instead of solving the Navier-Stokes equation by th...

In this paper dynamics of a vapour bubble generated due to a local energy input in the vicinity of a thin metal plate in the absence of the buoyancy forces is investigated. The bubble is initially generated in different distances from the surface and during its growth and collapse phases, it deforms the plate. The boundary Integral Equation Method...

Dynamics of a vapour bubble generated due to a high local energy input near a circular thin bronze plate in the absence of the buoyancy forces is numerically investigated in this paper. The bubble is generated near a thin bronze plate and during the growth and collapse of the bubble, it deforms the nearby plate. The Boundary Integral Equation Metho...