Study of waves on rising liquid films

Abstract

Only a l imited number of such measurements of wave p a r a m e t e r s for r is ing liquid films have however been made and mos t of these data were obtained at high flow ra tes (q > 0.8 cm2/sec) [3-6] at which entrainment occurs . Results obtained by various workers a re not in agreement . For example, m e a s u r e ments [7, 8] of the wave amplitude suggest that this is independent of the nature of the film flow and has a constant value (a -~ 0.27 according to [7] and a ~ 1 according to [8]). Other measurements [9] suggest that the amplitude does depend on the flow and var ies (a = 0.46-0.86). These d isagreements must resul t f rom the use of different measur ing techniques. The measurements [9] were obtained indirect ly by calculation from the e lectr ical r es i s t ance of pa r t of the flow tube, assuming a sinusoidal profi le of liquid surface, which assumption introduced an unquantifiable e r r o r into the calculation.