Research Areas

Storm Surge, Tide, Wave, and Mangroves

After moving to the United States, Dr. Chen broadened his research from fluid–structure interaction (CFD) to storm-surge, tide, and wave modeling. He works with both the in-house Coastal and Estuarine Storm Tide (CEST) model—developed at Florida International University’s International Hurricane Research Center—and the open-source TELEMAC suite maintained by a European consortium. CEST runs on a structured orthogonal curvilinear grid and emphasizes forecast efficiency and accuracy; it has been approved for transition into National Hurricane Center (NHC) operations. Among his contributions, Dr. Chen developed a mangrove module that represents landscape-scale biological characteristics—moving beyond traditional Manning’s-n roughness methods—(see Chen et al. (2021)). He also collaborates widely to advance CEST with subgrid features, operational forecasting capabilities, and the state-funded Florida Public Flood Loss Model project. With TELEMAC (specifically TELEMAC2D + TOMAWAC), he conducts coupled surge-tide-wave studies, including work on current–wave interactions around Puerto Rico during Hurricanes Irma and Maria (2017) (see Chen et al. (2024)). 

Renewable Wave/Wind Energy

Dr. Chen models wave energy converters (WECs) and floating offshore wind platforms (FOWP) using his 3D parallel Particle-In-Cell (PIC) model.  One project he has worked on is optimizing a wave energy converter-type floating breakwater system to achieve a balanced and optimal performance of both wave attenuation (as a breakwater) and wave energy absorption (as a wave energy converter) (see details in Chen et al. (2020)). He also compared the performance of the PIC model with the OpenFOAM model through various WEC applications (see details in Hao et al. (2024)). The 3D parallel PIC model also includes a quasi-static mooring system and is capable of simulating wave interaction with multiple floating structures.

Fluid-Solid Mixture Flow

Dr. Chen studies fluid–solid mixture flows using the Particle-in-Cell (PIC) framework. His research explores two fluid-structure interaction (FSI) strategies: (1) a resolved, strong, two-way coupled cut-cell method on grids fine enough to represent individual solids, where integrated fluid pressures on the wet surface (viscosity-related drag force neglected) drive solid motion; and (2) an unresolved approach in which fluid effects are modeled as drag, added-mass, and pressure-gradient forces, allowing particle sizes far smaller than the grid and thus very large populations. In both cases, solid–solid interactions are handled with the Discrete Element Method (DEM). Applications include modeling the dumping of engineering materials/waste into coastal waters, with and without fallpipes. One of Dr. Chen's projects was to study fall-pipe rock dumping with consideration of both coarse rocks and fine suspended particles. His publications in this area include Chen et al. (2019, 2023).

Particle-In-Cell model

Dr. Chen is probably the first coastal scientist to develop, from scratch, a three-dimensional (3D) parallel Particle-In-Cell (PIC) method-based Computational Fluid Dynamics (CFD) model for coastal and ocean engineering applications. CFD models are essential in the design, optimization, and maintenance of coastal and ocean infrastructures. While the widely accepted CFD models in the field often rely solely on either the Eulerian (e.g., OpenFOAM) or Lagrangian (e.g., SPHysics) frameworks for solving fluid flow equations, Dr. Chen’s PhD (and ongoing) research innovatively adopts the hybrid Eulerian-Lagrangian PIC method, which combines the strengths of both Eulerian and Lagrangian methods to achieve numerical accuracy, efficiency, and flexibility simultaneously (much like a hybrid gas-electric car). But it was no easy task; when applied to those complex engineering problems, the original PIC method suffers from numerical difficulties such as low accuracy, instability, mass loss, demanding memory requirements (due to the double grid system), difficulty in handling fluid-structure interaction, etc. Dr. Chen's 3D PIC model was parallelized using the domain-decomposition MPI approach and is a strong proof of concept of hybrid models for use in coastal and ocean engineering applications; as shown in a Blind Test organized by the UK CCP-WSI group and participated in by a dozen research groups worldwide, the 3D parallel PIC model achieved very competitive, if not the best, results (see Ransley, et al., (2020a) and Ransley, et al. (2020b)). Details of the PIC model can be found in Dr. Chen's publications and PhD thesis (CV link on the top-right corner of this page).

Tank Sloshing Under Wave Excitation with SPH method, potential flow theory, and experiments

Dr. Chen studies the liquid sloshing phenomena within tanks with forced motions or free wave excitations (e.g., LNG ships). For the inner sloshing domain, the SPHysics model was adopted with a new mirror boundary condition developed. For the external wave excitation, the potential flow theory was employed to provide the frequency-domain coefficients for the time-domain motion equation (the Cummins method), in which the sloshing force is added:

Dr. Chen also designed, carried out, and analyzed a series of flume experiments on tank sloshing during his master's degree study at DUT.

 爱与慈悲心

Love & Compassion