Zhongquan Charlie Zheng

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A modified immersed-boundary method is developed using the direct-forcing concept. An improved bilinear interpolation/extrapolation algorithm is implemented for more accurate boundary forcing expressions and easier implementation. Detailed discussions of the method are presented on the stability, velocity interpolation on the immersed boundary,(More)
Determination of distributions of nanoand micro-sized particles throughout chambers and enclosures with particle injections is very important for many agricultural, industrial and military applications such as indoor air quality, combustion, and species distributions. Most of the studies in a chamber environment with particle injections deal with uniform or(More)
A thin-tube vortex method is developed to investigate the intrinsic instability within a counter-rotating vortex pair system and the e ects from the core size and the wavenumbers (or wavelengths). The numerical accuracy and the advantages of the scheme are theoretically estimated. A nearest-neighbour-image method is employed in this three-dimensional vortex(More)
Related Articles Detuned resonances of Tollmien-Schlichting waves in an airfoil boundary layer: Experiment, theory, and direct numerical simulation Phys. Fluids 24, 094103 (2012) Effect of a splitter plate on the dynamics of a vortex pair Phys. Fluids 24, 074110 (2012) Effect of plate thickness on particle deposition velocity onto a face-up flat plate(More)
A time-domain solver using an immersed boundary method is investigated for simulating sound propagation over porous and rigid barriers of arbitrary shapes. In this study, acoustic propagation in the air from an impulse source over the ground is considered as a model problem. The linearized Euler equations are solved for sound propagation in the air and the(More)
An Euler-type gas/particle two-phase flow numerical model is presented for simulating the deposition of particles of tens of microns. At this size range of particles, the dominant effect considered for deposition on the bottom surface is gravitational settling. The mass conservation equation for the particulate phase is developed and simulated to include(More)
Nonlinear responses to a transversely oscillating cylinder in the wake of a stationary upstream cylinder are studied theoretically by using an immersed-boundary method at Re=100. Response states are investigated in the three flow regimes for a tandem-cylinder system: the “vortex suppression” regime, the critical spacing regime, and the “vortex formation”(More)