Abstract
CFD simulations based on LES was applied for the thermal striping phenomenon in a T junction pipe. The CFD models of several mesh size were used to evaluate grid convergences for temperature fluctuations. Fluid temperature fluctuations show some grid dependencies, but metal temperature fluctuations show good grid convergences and its order is same as experiments. These results means that high frequency temperature fluctuations induced by local flows like a karman vortex can be represented. Another important issue is to find some signs of low frequency temperature fluctuations by the branch stream swaying. Low temperature frequency fluctuations has possibilities to cause serious thermal fatigue damages in piping. A hypothesis of the mechanism of branch stream swaying was presented.
