Documento completo qui
Skin-friction drag reduction and power saving of pulsating turbulent channel flow have been numerically examined. Spatially uniform streamwise pressure gradient is modulated in time to generate the pulsating flow; its cycle-averaged value is constrained to be equal to the respective steady case one. The cycle-averaged Reynolds number, based on skin friction velocity and half channel height, is set at Retau=180. The forcing strategy corresponds to a simple periodic on/off switch of the pumping system.
The effectiveness of pulsating pumping has been examined through Direct Numerical Simulation (DNS): a preliminary and very coarse parametric study has been carried out in order to investigate the trend of drag reduction and power saving rates, by varying forcing periods and duty-cycle. Important results in terms of drag reduction and power saving have been obtained through this control technique; they certainly warrant further research in this area.