Abstract. Experimental investigation of spreading rate variation of liquid droplet under the conditions of its free-falling on a heated surface has been executed. Effect of surface temperature of flexible copper substrate on spreading rate variation of liquid droplet under the conditions of its free-falling has been studied. It has been found that the curve of liquid drop spreading rate changes exponentially. The spreading rate after time point of 0,002s assumes constant values V = 0.3 ÷ 0.5 m/s and does not depend on the surface temperature. Also it has been found that liquid drop spreading rate does not depend on the surface temperature at temperatures up to 108°С. Continued heating results in an increased liquid drop spreading rate and reaches a maximum values at temperature of 140°C. By heating the surface over 140°C the decreasing of spreading rate is occurred.

Abstract. Present work performs experimental investigation of the changes in the geometric shape of the drop in terms of its free-falling, depending on the conditions of drop formation on dispenser. It was found that volume and velocity of drop formation on dispenser are the factors affecting the geometric shape of the drop in terms of its free-falling.

Abstract.We conducted an experimental study of a heated substrate wetting by drops of distilled water under the conditions of their free-falling. The studies were conducted using a shadow system, which consists of a light source, lens and high-speed video camera. It was found that the maximum wetted area of drop is directly proportional to its volume. The main ranges of evolution of distilled water drop behavior on the heated surface (change of geometry at contact with the surface) have been conditionally divided.