<prompt> Turbulence of blood flow increases whenViscosityDiameter of blood vesselDensityStraight aeries  <response>: According to Reynold;s equation: Re rDVeWhere Re is the Reynolds number, named for the man who described the relationship; r is the density of the fluid; D is the diameter of the tube under consideration; V is the velocity of the flow, and e is the viscosity of the fluid.The higher the value of Re, the greater the probability of turbulenceTherefore increase in diameter cause increase in Re and hence increase turbulenceRef: Ganongs Review of Medical Physiology Twenty-Third Edition Page No:540 