Pulsed flow pressure waveforms

An experimental case-study [9] of ink jet printing was considered to validate the computer simulations, where p =1000 kg/m, p=1.3 mPa-s, G = 60 mN/m, = 20 pm, flowrate = 38.4 ml/h, tp ig = 100 ps. Drop formation and break up were predicted at about 50 pm distance from the nozzle. The falling droplet grew and evolved to a cap. The experimental case study showed many similarities, including the droplet break up time of about 123 ps, which agrees very well with the predictions. However, the predicted travelled distance is smaller than in the experiment. This is attributed to the fact that the experiment is not under constant flow rate during the pulse. As a result, the computer model needs modifications to account for a pressure waveform at inlet. 

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