We studied splashing on both smooth and rough dry surfaces using high speed photography. For smooth substrates, a striking phenomenon is observed: splashing can be completely suppressed by decreasing the pressure of the surrounding gas. The threshold pressure where a splash first occurs is measured as a function of the impact velocity and found to depend on the molecular weight of the gas and t...

(i) A study of the fluids in simple flow situations, such as those found in Rheometry. (ii) The construction of suitable constitutive equations for the non-Newtonian fluids under test. (iii) The use of these constitutive equations in the prediction of behavior in complex flows of practical importance. (iv) An experimental study of the behavior of non-Newtonian fluids in the complexflow situatio...