Flow separation control by pulsed corona actuators

Discharge Stability Enhancement in Surface Corona Actuators

“…It is worth noting that the power measured at the primary has a different trend, with a minimum around 800Hz already detected in the tests of actuator C6 with wider electrodes in the wind tunnel [15], due to the resonance of the transformer connected to the circuit, a known phenomenon already highlighted in literature [25].…”

“…The data were collected for a frequency range between 400Hz and 1.5kHz, including the 800 Hz excitation that permits direct comparisons with the results provided in [15] at this frequency, concerning wind tunnel tests on the same actuator applied to a stall control problem.…”

“…Lowering the DC voltage of the present actuator to V DC =13.0 kV, the measured power/length ratio is 20 W/m, consistent with the 16 W/m measured on a longer version (0.4m) of C6 at the same V DC [13] by observing that in the power/length ratio the end effects are increasingly important on shorter electrodes. Another 0.4m long C6 was tested in pulsed mode with f = 800 Hz on a wind tunnel airfoil [15] and operated at V pk =13.0 kV, with a power consumption of 14.7 W/m. This power is close to the present value in spite of the lower voltage set in wind tunnel tests, however this can be explained by considering that the corona current and power increase when the discharge is subjected to an overlapping gas flow in the same direction, a known phenomenon evidenced both for surface and volumetric corona discharges [26].…”

“…Albeit considerations in the following sections apply to the entire class of multi-tip devices, this particular specimen was selected to allow for comparison of bench results with the ones obtained in wind tunnel tests [15], where this actuator showed remarkable lift and drag enhancement in incipient and deep stall conditions when the same power supply here considered was applied. Here the chosen PMMA dielectric substrate is the same of the wind tunnel version, however further experiments could involve non hygroscopic materials as glass or SiO 2 crystals, capable to influence the actuator performance [5], [16].…”

Recent Developments in Air Pumps for Thermal Management of Electronics

“…On the other hand, EHD pumps are flexible in the electrode design so that EHD pumps can be configured in a small or irregular space. Besides, EHD flow is also known to be useful in the boundary layer control [89,90], and thus the heat transfer enhancement [91,92]. Furthermore, EHD pumps have no moving parts, making the silent operation possible [80,93].…”