The effect of spatial incoherence in surface temperature fluctuations on the stress intensity factor in thermal striping

When incompletely mixed hot and cold fluid streams pass adjacent to the surface of a component of a structure, they can cause that component to suffer thermal fatigue damage. Spatial incoherence in the thermal fluctuations will affect the stress intensity factor (SIF), which is frequently calculated assuming perfect spatial coherence. A model is developed to assess this effect for a circumferential line crack in a thin cylinder. The dimensionless SIF can be increased or decreased by reduced spatial coherence, depending on a combination of factors such as Fourier number, Poisson ratio, scale of coherence and crack depth.