Research & Industry

My research focuses on investigating the intricate dynamics of turbulent flows and the development of novel technologies in numerical and experimental Aero-/Hydro-dynamics. The field of offshore engineering has seen significant innovation in recent years due to the increasing number of operations moving further out to sea. Offshore wind turbines, wave energy converters as well as autonomous service vessels all represent possibilities for novel research and development. Detailed Aero-/Hydro-turbulent analyses are necessary to properly design, build, maintain, and optimize the performance and dynamics of these structures and platforms. My research centers on numerical Aero-/Hydro-dynamics for renewable engineering. Combining numerical simulations, experimental testing, and machine learning, I aim to deepen our understanding of turbulent flows in offshore renewable energy devices.

Research/Industry Experience

The University of Texas at Dallas, 

Starting Fall 2024

Graduate Research Assistant

Advisor: Professor Kianoosh Yousefi.

Projects: 

Contributions:

Stevens Institute of Technology, 

Spring 2019 - Summer 2020

Texas A&M University, 

Fall 2020 - Fall 2023

Graduate Research Assistant

Advisor: Professor Mirjam Fürth.

Projects: Hydrokinetic Flapping Foil Turbines, Point Wave Energy Converters, Oscillating Cylinder, and Planing High-Speed Crafts.

Contributions:

Front Energies, LLC
Floating System Engineering

Summer 2022

Research & Development Engineering Intern

PI: Dr. Zhirong Shen.

Projects: Floating Offshore Wind Turbines.

Contributions:

Research Skills & Interests

Programming & CFD Tools: Proficient in Fortran, OpenFOAM, Mathematica, C++, GitHub, Python, Bash, Linux HPCFD, SLURM, LATEX, OpenFAST, NEMOH, Matlab, R, TensorFlow, & Keras.

Commercial Software: Proficient in SolidWorks and AutoCAD and Good in Fluent ANSYS

Interests: 

Research Collaborations

Biolistic Drug-Delivery

July 2024 - Present

Collaborator

Advisors: 

Ship Hull Optimization

May 2022 - May 2024

Developed codes to reduce the wave resistance over a KCS hull by optimizing its shape.

Advisors: 

Turbulent PANS Model

January 2023 - August 2023

Implemented different turbulent PANS models in OpenFOAM and performed validation simulations.

Advisors: 

Modified OverSet Mesh in OpenFOAM

May 2022 - March 2024

Developed a modified OverSet meshing technique to simulate deformable moving bodies, such as flexible flapping foils, see GitHub link.

Improving the coupling library between OpenFOAM and PreCICE to perform a Fluid-Solid Interaction (FSI) simulation.

Developed with Ph.D student Karim Ahmed, Universite de Poitiers.

Advisors: 

Research Mentoring/Co-Advising

Vertical Axis Wind Turbine - AIAA CLUB

July 2024 - Present

Investigated the separation phenomenon over a straight blade vertical axis wind turbines through cross-flow fan integration.

Students: 

Main Advisors: 

 Heat Transfer from a Channel

September 2021 - Present

Investigated the naturally-driven flow behavior in channels with different aspect ratios.

Students: 

Main Advisors: 

Machine Learning in CFD of Transonic Flow over an Airfoil

Septemeber 2022 - October 2023

Proposed an approach to estimate the aerodynamic coefficients of airfoils in the transonic regime using Artificial Neural Networks.

Students: 

Main Advisors: 

Point Wave Energy Converters

January 2021 - May 2023

Investigated different shaped surface buoys, with a focus on the power-generating ability of the system, for a single point WEC at different waves.

Students

Main Advisors: 

Research Topics

Figure: Unsteady compressible viscous transonic flow over an airfoil with a morphing bump.

Figure: Mesh motion results for the case of a flexible flapping wing during a flapping cycle.

Figure: Folder structure of TurbulenceModels library, showing the implementation location of different models.

Figure: Folder structure of TurbulenceModels library, showing the implementation location of different models.

Computational Fluid Dynamics

My research endeavors encompass a multifaceted approach to advancing computational fluid dynamics (CFD) techniques in a diverse array of engineering domains. Leveraging my expertise in building in-house finite element method (FEM) and finite volume method (FVM) codes in Fortran and C++, I have developed robust tools for simulating both steady and unsteady incompressible and compressible flows, spanning from basic Euler equations to more complex Navier-Stokes formulations.

Embracing the principles of Object-Oriented Programming (OOP), I have contributed to the development of shape optimization code using Fortran. In addition, I gained the skills of dealing with different types of dynamic meshes, such as morphing and overset meshes, as well as implementing fixed meshes such as Volume-of-Fluid (VOF) and Level Set Method (LSM) in both Fortran and OpenFOAM (C++) environments. 

My proficiency in parallelization techniques for High-Performance Computing (HPC) environments has been instrumental in optimizing computational efficiency. Notably, my contributions include developing libraries for mooring coupling, refining overset methods to accommodate simultaneous rigid body motion and deformation, and implementing PANS in turbulent modeling.

Figure: Compressible turbulent flow over a triangle airfoil using RANS and PANS turbulent

Turbulent Modeling & Machine Learning

Leveraging advanced turbulence modeling techniques, including Reynolds-Averaged Navier-Stokes (RANS), Partially-Averaged Navier-Stokes (PANS), and Implicit Large Eddy Simulation (ILES), I have delved into understanding the intricate interplay of turbulent structures and their impact on fluid behavior. Recognizing the limitations of traditional modeling approaches, I will embark on integrating machine learning (ML) and deep learning (DL) techniques into turbulent simulations to augment predictive accuracy and efficiency. By harnessing the power of ML algorithms, such as neural networks and deep learning models, I aim to uncover hidden patterns within turbulent flow data and develop novel methodologies for turbulence modeling and prediction. Through projects like ML-based lift coefficient prediction for transonic airfoils (Ayman et al., 2023) and participation in OpenFOAM-Machine Learning Hackathons, I have enriched my knowledge in AI technologies and their potential for revolutionizing turbulent flow simulations. Moving forward, I am committed to further exploring the synergies between turbulent simulations and machine learning, with the ultimate goal of advancing our understanding of turbulent flows and driving innovation in engineering design and optimization.

Figure: Schematics of a WEC with a cylindrical buoy (Hamada & Fürth, 2021a). 

Wave Energy Converters

One way to improve the effectiveness of the Point Wave Energy Converters (PWEC), is to optimize the buoy shape, increasing its response motions and subsequently improving the power extraction efficiency. However, the literature does not provide a single universally optimized buoy shape; it changes from study to study along with the wave characteristics (Hamada & Fürth, 2021 & 2022). Recently, the scientific community has been focusing on developing a Variable Shape PWEC, which can harvest wave energy efficiently over a wide range of sea states. The first VSPWEC was proposed by Zou & AbdelKhalik (2020). This buoy can change its shape depending on the incident wave’s characteristics. With the use of active shape optimization, optimal control algorithms, and excitation wave estimation, VSPWEC can outperform Fixed Shape PWECs due to their wider optimal operation ranges and less complex PTO units (Zou et al., 2021). The existing literature on VSPWECs relies on potential solvers and low-fidelity simulations. However, these methods may not capture the full complexity of turbulent dynamics in such applications. Therefore, there is a critical gap in understanding the turbulent behavior of VSPWEC systems, particularly regarding their interaction with the mooring system, Power Take-Off system, irregular sea waves, and harsh sea conditions. Addressing this gap through detailed turbulent simulations is essential for advancing our knowledge and optimizing the design and performance of VSPWECs. Leveraging recent advancements, such as the overset method and the integration of PANS in OpenFOAM (Ahmed et al., 2024) facilitates the execution of these simulations, offering a pathway to comprehensive understanding and optimization.

Figure: Vorticity contours around a NACA 0012 flapping foil in swing-arm mode during the down-stroke phase (Hamada & Fürth, 2023)

Flapping-foil hydrokinetic turbine

The VIV phenomenon also appears over streamlined bodies, such as foils, at high angles of attack. The flapping foil generates power by performing two main motions: heave and pitch. The main indication of the power extraction capability for the flapping-foil is the strength of the Leading-Edge Vortex (LEV) (Hamada & Fürth, 2022 & 2023). Hence, the gained power starts to fade out when the stall phenomenon appears (Karbasian et al., 2016). High-lift devices will delay the stall phenomenon of the LEV over the flapping foils. However, which type of high lift device, (flap, slat, cuff, and air slots) is the best and the time of its operation during the flapping cycle is still unclear. In addition, expanding from 2D to 3D, biomimicry from the fish fin will be used to improve the performance of the flapping foil. The motion of a fish’s fin during swimming is very similar to the flapping foil motion, simplifying the fish’s fin motion to be a rigid body, Qiang Zhong et al. (2021) showed that the induced vortices, generated during the flapping motion of the fin, are highly affected by the shape of the fish’s fin. Thus, the bio-inspired shapes from near-ground swimming fishes will increase the efficiency of energy harvesting using the flapping foil operating near the ground. However, the determination of the geometric parameters of the flapping foil, such as the aspect ratio, sweep angle, taper ratio, and twist angle is still an open area of research.

Floating Offshore Wind Turbines

Figure: FOWT subjected to a focus wave.

Floating Offshore Wind Turbines (FOWTs) have attracted growing attention in recent years due to their enormous potential to harvest wind energy in deep-water offshore regions. Numerical modeling of the moored FOWT system is important to provide an accurate and reliable CFD for moored offshore systems. Enhancing my proficiency in the realm of Floating Offshore Wind Turbines (FOWTs), I have directed my focus towards conducting high-fidelity simulations of extreme waves on these offshore structures. Employing various OpenFOAM libraries, such as Iso-Advector, waves2foam, FocusedWave, Adaptive Mesh Refinement (AMR), Overset, MoorDyn, and FloatStepper, I have endeavored to capture the intricate dynamics of wave-structure interactions. Through these simulations, I aim to unravel the intricate dynamics of turbulent flows, encompassing hydrodynamic, aerodynamic, and structural phenomena within FOWTs. Specifically, the research aims to elucidate the complex interactions between these factors, with a primary focus on the wake-wind-wave interaction and its influence on the performance and integrity of floating offshore wind farms.