Interaction between liquid drop with low impact momentum and heated wall

Interaction between an impinging liquid drop with low momentum and a heated wall is investigated experimentally, using a high-speed digital camera with capacity of 10${}^6$ frames per second. Wall temperature ranges in 47–108 ${}^{\circ }$C, and Weber number varies from 4 to 67. Water is selected as the fluid due to its relatively high surface tension. Results reveal that both drop spreading scale and height present a damped oscillation process. In particular, spreading appears a large damping feature, while the drop height pertains to small damping. In order to describe drop oscillation more accurately, a damping model is proposed to fit the experimental data of the dimensionless drop height. The effect of wall temperature and Weber number on the peak value of height and the dimensionless angular frequency in the damping model is discussed, suggesting that the Weber number is the determinant and influences of wall temperature are minor. With increasing Weber number, the dimensionless angular frequency descends exponentially. Also a theoretical model used to predict this dimensionless angular frequency is obtained successfully by derivation, which is proportional to − 0.5 power of the Weber number. Finally, an empirical correlation for the water drop is provided.