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Low Reynolds number laminar channel flow is used in various heat/mass transfer applications such as cooling and mixing. A low Reynolds number implies a low intensity of heat/mass transfer processes since they rely only on the gradient diffusion. To enhance these processes, an active flow control by means of synthetic (zero-net-mass-flux) jets is proposed. The present study is experimental, in which a Reynolds number range of 200–500 is investigated. Measurement has been performed mainly in air as the working fluid by means of hot-wire anemometry and the naphthalene sublimation technique. Particle image velocimetry (PIV) experiments in water are also discussed. The experiments have been performed in macroscale at the channel cross sections (20×100) mm and (40×200) mm in air and water, respectively. The results show that the low Reynolds number channel flow can be influenced by an array of synthetic jets. The effect of synthetic jets on the heat transfer enhancement is quantified. The stagnation Nusselt number is enhanced by 10–30 times in comparison with the nonactuated channel flow. The results indicate that the present arrangement can be a useful tool for heat transfer enhancement in various applications, e.g., cooling and mixing.

Low-Reynolds-number laminar channel flow is used in various heat/mass transfer applications, such as cooling and mixing. A low Reynolds number implies a low intensity of heat/mass transfer processes, since they rely only on the gradient diffusion. To enhance these processes, an active flow control by means of synthetic (zero-net-mass-flux) jets is proposed. This arrangement can be promising foremost in microscale. The present study is experimental in which a Reynolds number range of 200–500 is investigated. Measurement was performed mainly in air as the working fluid by means of hot-wire anemometry and the naphthalene sublimation technique. PIV experiments in water are also discussed. The experiments were performed in macroscale at the channel cross-section (20×100)mm and (40×200)mm in air and water, respectively. The results show that the low Reynolds number channel flow can be actuated by an array of synthetic jets, operating near the resonance frequency. The control effect of actuation and the heat transfer enhancement was quantified. The stagnation Nusselt number was enhanced by 10–30 times in comparison with the non-actuated channel flow. The results indicate that the present arrangement can be a useful tool for heat transfer enhancement in various applications, e.g., cooling and mixing.