Master of Science (MS)
In this study the effect of uncertainty of velocity ratio on jet in crossflow and particual- rly film cooling performance is studied. Direct numerical simulations have been combined with a stochastic collocation approach where the parametric space is discretized using Multi-Element general Polynomial Chaos (ME-gPC) method. Velocity ratio serves as a bifurcation parameter in a jet in a crossflow and the dynamical system is shown to have several bifurcations. As a result of the bifurcations, the target functional is observed to have low-regularity with respect to the paramteric space. In that sense, ME-gPC is particularly effective in discretizing the parametric space. One particular case of a jet in a crossflow is numerically solved with the velocity ratio variations assumed to have a truncated Gaus- sian distribution with mean of 1.5 and the standard variation of approximately 0.5. Five elements are used to discretize the parametric space using ME-gPC method. Within each element general polynomial chaos of order 3 is used. A fast convergence of the polynomial expansion in the parametric space was observed. Time-dependent Navier-Stokes equations are sampled at Gauss-quadrature points using spectral/hp element method implemented in NEKTAR. Overall due to the low-regularity of the response surface, ME-gPC is observed to be a computationally effective strategy to study the effect of uncertainty in a jet in a crossflow when velocity ratio is the random parameter.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Babaee, Hessam, "Uncertainty quantification of film cooling effectiveness in gas turbines" (2013). LSU Master's Theses. 1389.