to p by p v divided by half rho v square p minus p v. p is the pressure of the liquid at the point under consideration, p v is the vapor pressure of the liquid. So, p minus p v, if it is 0, then cavitation will occur, isn’t it? Theoretically, it may be plus minus this, but theoretically, when this p minus p v is 0 or this cavitation number is 0, cavitation should occur. Half rho v square, rho we know density of water, v is the speed of water. This gives you the dynamic effect, the v. So theoretically, when sigma is 0, we should have cavitation.