@article{wan_roberts_kuznetsov_2005, title={Computational analysis of the feasibility of a micro-pulsejet}, volume={32}, ISSN={["1879-0178"]}, DOI={10.1016/j.icheatmasstransfer.2004.05.020}, abstractNote={This paper investigates the feasibility of a 2-cm micro-pulsejet by numerically simulating the inviscid gas dynamic phenomena within the exhaust tube and comparing them with those for a pulsejet on the order of 50 cm in length. After initial combustion, the pressure wave propagates towards the exit and reflects back as a rarefaction wave, which generates a minimum pressure in the combustion chamber. This low pressure must be sufficient to open the reed valves to allow fresh reactants to enter. It is shown that for both large and micro-pulsejets, the minimum pressure is low enough. The characteristic operating frequency is found to be approximately inversely proportional to the pulsejet length. Estimation of the boundary layer thickness in the pulsejet shows that viscosity plays a very significant role in the micro-pulsejet and cannot be neglected.}, number={1-2}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Wan, Q and Roberts, WL and Kuznetsov, AV}, year={2005}, month={Jan}, pages={19–26} }
@article{wan_wu_chastain_roberts_kuznetsov_ro_2005, title={Forced convective cooling via acoustic streaming in a narrow channel established by a vibrating piezoelectric bimorph}, volume={74}, ISSN={["1573-1987"]}, DOI={10.1007/s10494-005-4132-4}, abstractNote={Forced convection in a narrow channel is investigated both numerically and experimentally. The flow field is established through the mechanism of acoustic streaming. This is accomplished by high frequency vibration of one of the channel walls, which is composed of a piezoelectric bimorph. In the numerical computations, the Navier-Stokes equations are decomposed into the acoustic equations and the streaming equations by the perturbation method. The acoustic field is first numerically obtained, which provides the driving force for the streaming field. The streaming field and the associated temperature field are then obtained numerically. Heat losses from a heat source are measured to determine the efficiency of this as a cooling method. The air-flow patterns in the channel between the heat source and the bimorph actuator are visualized using the particle tracking velocimetry. The visualization clearly shows that vortical streaming (acoustic streaming) can be induced by bimorph vibration, which enhances heat transfer between the heat source and the surrounding air. The temperature decreases obtained computationally and experimentally are in good agreement.}, number={2}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Wan, Q and Wu, T and Chastain, J and Roberts, WL and Kuznetsov, AV and Ro, PI}, year={2005}, month={Mar}, pages={195–206} }
@article{wan_kuznetsov_2005, title={Investigation of hysteresis in acoustically driven channel flow at ultrasonic frequency}, volume={47}, ISSN={["1521-0634"]}, DOI={10.1080/1047780590885873}, number={2}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Wan, Q and Kuznetsov, AV}, year={2005}, month={Jan}, pages={137–146} }
@article{wan_kuznetsov_2004, title={Investigation of the acoustic streaming in a rectangular cavity induced by the vibration of its lid}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(04)00028-4}, abstractNote={In this paper, the Network Simulation Method (NSM) is used to model an unsteady, viscous, flow problem: the heated lid-driven filled with nanofluid and in the presence of a pulsating flow. Through this method is analyzed the influence of the amplitude, wave number and oscillation frequency of sinusoidal velocity waves at the lid on the convection performance of the cavity. It is stated that this method is simple and efficient for solving unsteady, viscous, Navier–Stokes equations, through the design and resolution of an electrical circuit network whose equations are formally equivalent to the ones of the fluid flow problem. Results show that, for the case of Pr = 3.93, Re = 50, Ri = 11.82, sinusoidal velocity waves at the lid increase the time-averaged Nusselt number in the cavity with respect to the non-pulsating case up to a 16%. This is due to enhancement of the transport phenomena induced by the pulsating flow.}, number={4}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Wan, Q and Kuznetsov, AV}, year={2004}, month={May}, pages={467–476} }
@article{wan_kuznetsov_2004, title={Streaming in a channel bounded by an ultrasonically oscillating beam and its cooling efficiency}, volume={45}, ISSN={["1040-7782"]}, DOI={10.1080/1040778049026739}, abstractNote={In this article the oscillating and streaming flow fields in a channel composed of two long parallel beams, one of which is stationary and the other of which oscillates with an ultrasonic frequency in a standing wave form, are investigated. The perturbation technique is utilized under the assumption that the oscillation amplitude is much smaller than the channel width and that the Reynolds number, which is defined by the oscillating frequency and the standing wave number, is much greater than unity. A three-layer structure of both the oscillating and streaming flow fields, which is composed of two very thin boundary layers near the beams and the core region between the boundary layers, is found in the channel. The oscillating velocity fields in all three layers are obtained analytically. The streaming fields within both boundary layers are also obtained analytically based on the oscillating fields. It is found that the streaming velocities approach constant values at the edges of the boundary layers and thus provide slip velocities for the streaming field in the core region. The core-region streaming velocity field is then obtained numerically by solving the Navier–Stokes equations in the stream function–vorticity formulation. Based on the core-region streaming field, which dominates most of the channel, the temperature field is computed for two cases: both beams are kept at constant but different temperatures (case A); and the oscillating beam is kept at a constant temperature while the stationary beam is subjected to a uniform constant heat flux (case B). Cases of different channel widths are computed and a critical width is found. When the channel width is smaller than the critical one, for each half standing wavelength distance along the beams, two symmetric eddies are observed, which occupy almost the whole width of the channel. In this case, the Nusselt number increases with the increase of the channel width. After the critical width, two layers of asymmetric eddies are observed near the oscillating beam and the Nusselt number decreases and approaches unity with further increase of the channel width. The abrupt change of the streaming field and the Nusselt number as the channel width goes through its critical value may be due to a bifurcation caused by instability of the vortex structure in the fluid layer.}, number={1}, journal={NUMERICAL HEAT TRANSFER PART A-APPLICATIONS}, author={Wan, Q and Kuznetsov, AV}, year={2004}, month={Jan}, pages={21–47} }
@article{wan_kuznetsov_2003, title={Effect of non-uniformity of source vibration amplitude on the sound field wave number, attenuation coefficient and Reynolds stress for the acoustic streaming}, volume={30}, ISSN={["1879-0178"]}, DOI={10.1016/S0735-1933(03)00004-6}, abstractNote={The aim of this paper is to analytically solve the sound field generated by a standing wave induced in a vibrating beam. This case is different from a plane wave which is the traditional way of inducing acoustic streaming. The analytical solution shows that the amplitude non-uniformity can be represented by a non-uniformity coefficient y, which characterizes the ratio of the wave number or the attenuation coefficient to their values for the classical plane wave case. The non-uniformity coefficient γ is also obtained by resolving the acoustic field utilizing full numerical solution. Numerical and analytical results are in a good agreement. The Reynolds stress generated by a beam vibrating at one of its modes is also calculated. The maximum values of the Reynolds stress are achieved at the anti-node coordinates and small negative minimum values of the Reynolds stress are observed at the node coordinates. An interesting four-vortex-per-wavelength structure is predicted for such sound field.}, number={1}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Wan, Q and Kuznetsov, AV}, year={2003}, month={Jan}, pages={27–36} }
@article{wan_kuznetsov_2003, title={Numerical study of the efficiency of acoustic streaming for enhancing heat transfer between two parallel beams}, volume={70}, ISSN={["1386-6184"]}, DOI={10.1023/B:APPL.0000004916.01838.63}, number={1-4}, journal={FLOW TURBULENCE AND COMBUSTION}, author={Wan, Q and Kuznetsov, AV}, year={2003}, pages={89–114} }