Omid Z. Mehdizadeh

Numeca International · FINE/Turbo Solver

The nonlinear harmonic method (NLH) for efficiently simulating unsteady turbomachinery fluid dynamics in the frequency domain is described, and the details of its application to inlet distortion are discussed. The method capabilities are then demonstrated on the NASA transonic fan Stage 67 with a generic inlet distortion. Comparison of the results...

High pressure turbine (HPT) optimum thermal design is critical in further improving gas turbine efficiency. However, this is a challenging task as it requires accurate simulation of unsteady flows in conjunction with heat transfer simulation of the airfoil solid structure, which in turn requires large computational resources. In this work, the non...

Turbulence modeling remains an active CFD development front for turbomachinery as well as for general industrial applications. While DNS and even LES still seem out of reach within the typical industrial design cycle due to their high computational cost, RANS-based models remain the workhorse of CFD. Currently, the most widely used models are Linea...

In this work, we evaluate an approach to flow-induced vibratory stress prediction on the high pressure compressor (HPC) stator vanes of a small turbofan engine, where strain gauge test data is available. The approach is based on fully-coupled fluid-structure interaction analysis in the time domain. In our evaluation, we consider the vibratory stres...

Inverse methods are presented for identifying the acoustic modal structure in a turbofan inlet using farfield noise measurements and high-fidelity, aeroacoustic radiation simulations. The reconstructed modal structure can potentially be used to gain insight into the noise source mechanism, to deduce corrective actions for hardware, and to analyze i...

A three-dimensional finite element method has been implemented to predict the transmission loss of a packed muffler and a parallel baffle silencer for a given frequency range. Iso-parametric quadratic tetrahedral elements have been chosen due to their flexibility and accuracy in modeling geometries with curved surfaces. For accurate physical repres...

A spectral element method is developed for solving the two-dimensional Helmholtz’s equation, which is the equation governing time-harmonic acoustic waves. Computational cost for solving Helmholtz’s equation with the Galerkin finite element method increases as the wave number increases, due to the pollution effect. Therefore a more efficient numeric...

A modal spectral element method is developed for solving the three-dimensional Helmholtz’s equation, which is the equation governing time-harmonic acoustic waves. Computational cost for solving three-dimensional Helmholtz’s equation increases significantly as the wave number increases, due to the required resolution per wavelength. Furthermore, for...