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Synthetic jet which is based on zero netto mass input but non-zero momentum is a new approach
utilized for cooling system. The synthetic air jet was generated by vibrating membranes which pushed out the air from the cavity through the exit nozzles with oscillatory motion. This research investigated the forced cooling characterization of a cross flow synthetic jet using double membrane actuator with two different variations of sinusoidal and square wave and was conducted in computational as well as experimental stage. Computational stage was conducted by a commercial CFD software of Fluent® with a turbulence model k- ω SST with meshing elements quad type pave, while in the experimental work the function generators was used to drive the membranes with the variation of sinusoidal and square wave in three oscillation frequencies i.e 80 Hz, 120 Hz, and 160 Hz at fixed amplitude of 0.002 m/s. The experimental results show significant effect of the reduction of the confinement effect phenomena by using the cross flow synthetic jet. The best heat transfer rate, hence the optimum cooling effect was obtained at a lower oscillation frequency; in this study at sinusoidal 120 Hz – sinusoidal 120 Hz.

Numerical simulations and experimental methods are conducted to discover the effect of various
distance between the orifice and the heated plated (L). The investigation focusing on the characteristics of convective heat transfer by a synthetic jet circular orifice. The results is verified by the time history of convective heat transfer characteristic and validated against existing experimental results. The model was simulated to investigate the dispersion of heat flow on the walls using a mathematical turbulent model of k-w SST. The Reynolds number (Re) is in the range of 1421-2843 based on average velocity, while the normalized impinging distance varies between 0 and 3.3. The movement of the piezoelectric membrane is assumed of sinusoidal wave function. The results showed the significant influence of L/d Ratio and sinusoidal wave frequencies to the heat transfer rate obtained. At small axial distance (L), average Nusselts number decrease due to confinement effect. However, at larger axial distances, the synthetic jet velocity weaken which again reduces the convective heat transfer coefficient.

A Synthetic jet works based on a vibrating membrane inside a cavity and nozzle for the air outlet. The synthetic jet cavity interior has an important role to generate the air at sufficient conditions to do the cooling process. This research investigated the flow and convective heat transfer characteristics on four impinging synthetic jet prototype with different excitation modes of a sinusoidal waveform forcing. The main purpose of this synthetic jet was to create vortices pair to come out from nozzle which will accelerate the heat transfer process occurring at the impinged wall. This heat transfer enhancement principles became the basis to simulate an alternative cooling system to substitute the conventional fan cooling in electronic devices due to its advantage for having a small form factor and low noise. The investigation combined computational and experimental works. In the experiment sinusoidal waveform was used to oscillate the membrane and the wave frequency used were 80 Hz, 120 Hz, 160 Hz and the velocity amplitude was 1 m/s. Some results indicated significant influence of the cavity design, frequency excitation, and waveform to the rate of heat transfer obtained.

This research examines the influence of turbulence model k-epsilon standar, k-epsilon realizable, k-omega standar dan k-omega SST (Shear Stress Transport) to determine the convective heat transfer for an impinging synthetic jet model. The prototype of synthetic jet has 20 outlet nozzle with a diameter size of each nozzle of 2 mm and is driven by two piezoelectric membrane that operate by 5 volts and create a sinusoidal wave. In this research the investigation was carried out by computational methods using the software CFD (Computational Fluid Dynamics) to resolve the turbulence models as well as experimental methods to validate the turbulence model by measuring the temperature for 3 minutes. Oscillation frequency of the piezoelectric membrane that drives the synthetic jet was set as 120 Hz with the amplitude 2 mm/s. The results shows that K-Omega turbulence model SST is better to simulate the synthetic jet stream that has a narrow slit as a flow passage

This research is a continuation of synthetic jet characteristics investigation over convective cooling of impinging jet model. The synthetic jet cooling uses an air flowing in a vertical direction into the heated wall. This model uses an oscilating membrane to push and pull the air from and to the cavity. The purpose of this model of synthetic jet is to create vortices pair to come out from nozzle which will accelerate the heat transfer process occurring at the wall. This heat transfer enhancement principle has became the basis to simulate an alternative cooling system in order to substitute the conventional fan cooling in electronic devices due to its advantage for having a small form factor and low noise. The investigation is conducted in the computational work. In this research, the synthetic jet prototype model was simulated to examine the distribution of heat flow on the walls using a mathematical turbulent model k-ω SST. Meshing order was elements Tet/Hybrid and type Tgrid and the number of grid was more than 233.886 in order to ensure detail discretization and more accurate
calculation results. This simulation used a triangular waveform as it excitation source. The frequencies of excitation were 80 Hz, 120 Hz, 160 Hz and the amplitude was 1 m/s. Using this variation, the main goal is to increase the heat transfer coefficient generated by the synthetic jet blow.