RAYLEIGH-TAYLOR INSTABILITY OF A CYLINDRICAL INTERFACE BETWEEN 2 INVISCID FLUIDS

A theoretical analysis for the instability of a fluid film around a cy linder in an immiscible fluid is presented. A general dispersion equat ion, relating wave number to Department al Mining and growth rate, is derived with consideration of the effects of the cylindrical interface and a finite film thickness. Application of the dispersion equation t o the breakup of a liquid film around a cylindrical body in still air leads to a prediction of the dominant wavelength by lambda = 2 pi root 2/root(1/R(2) + rho(1)g/q), where R is the radius of the cylinder, rh o(1) is the density of the liquid, g is the acceleration due to gravit y, sigma is the surface tension. Experiments showed good agreement wit h the present analysis. The dominant wavelength decreases with a decre ase in the radius of the cylindrical body. A previous report on the br eakup of a liquid film around a horizontal cylindrical body is shown t o be error.