Xiuling Wang

An h-Adaptive Finite-Element Technique for Constructing 3D Wind Fields

Abstract An h-adaptive, mass-consistent finite-element model (FEM) has been developed for constructing 3D wind fields over irregular terrain utilizing sparse meteorological tower data. The element size in the computational domain is dynamically controlled by an a posteriori error estimator based on the L2 norm. In the h-adaptive FEM algorithm, large element sizes are typically associated with smooth flow regions and small errors; small element sizes are attributed to fast-changing flow regions and large errors. The adaptive procedure employed in this model uses mesh refinement–unrefinement to satisfy error criteria. Results are presented for wind fields using sparse data obtained from two regions within Nevada: 1) the Nevada Test Site, located approximately 65 mi (1 mi ≈ 1.6 km) northwest of Las Vegas, and 2) the central region of Nevada, about 100 mi southeast of Reno.

A Dynamic LES Model for Turbulent Reactive Flow with Parallel Adaptive Finite Elements

An adaptive finite element method (FEM) is used for the solution of turbulent reactive flows in 3-D utilizing parallel methods for fluid dynamic and combustion modeling associated with engines. A dynamic LES method permits transition from laminar to turbulent flow without the assumptions usually required for turbulent sublayers near wall area. This capability is ideal for engine configurations where there is no equilibrium in the turbulent wall layers and the flow is not always turbulent and often in transition. The developed adaptive FEM flow solver uses “h” adaptation to provide for grid refinement. The FEM solver has been optimized for parallel processing employing the message passing interface (MPI) for clusters and high-performance computers.

A Meshless Method for Modeling Convective Heat Transfer

A meshless method is used in a projection-based approach to solve the primitive equations for fluid flow with heat transfer. The method is easy to implement in a MATLAB format. Radial basis functions are used to solve two benchmark test cases: natural convection in a square enclosure and flow with forced convection over a backward facing step. The results are compared with two popular and widely used commercial codes: COMSOL, a finite element model, and FLUENT, a finite volume-based model.Copyright

Numerical Simulation of Contaminant Dispersion Within an Aircraft Interior

A hybrid numerical model has been developed to simulate contaminant dispersion within an aircraft interior. A two-equation Low-Reynolds-Number adaptive FEM model is used for simulating turbulent flow within an aircraft. Coupled with Lagrangian Particle Transport Technique, contaminant dispersion within aircraft interiors can be accurately simulated. Mesh independent studies can be avoided when using the adaptive technology, an L2 norm error estimator is used to guide the adaptation procedure. By using the adaptive algorithm, mesh independent studies can be avoided.Copyright

Application of an HP-Adaptive Finite Element Method for Thermal Flow Problems

*† Numerical results are presented for a set of convective thermal flow problems using an hpadaptive finite element technique. The hp-adaptive model is based on mesh refinement and spectral order incensement to produce enhanced accuracy while attempting to minimize computational requirements. An a-posteriori error estimator based on the L2 norm is employed to guide the adaptation procedure. Example test cases consisting of natural convection in a differentially heated enclosure, flow with forced convection heat transfer over a backward facing step and natural convection within an enclosed partition are presented. Numerical results are compared with published data in the literature.