Observations on the Honji instability

A numerical investigation of three-dimensional sinusoidally oscillating flow around an infinitely long cylinder was conducted to examine the onset of the Honji instability and to gain insight into the mechanism that causes the Honji instability to arise. An attempt is made to quantify when the instability occurs using the dimensionless flow parameters of the Keulegan–Carpenter number (KC) and the Sarpkaya number (β). Through numerical analysis and an explanation of physics, it is shown that the Honji instability occurs through the mechanisms described by Lord Rayleigh, but is significantly different from the Taylor, Dean, and Görtler instabilities.