On-Demand - Frequency Domain Methods for Turbomachinery Unsteady Flow Simulation

Turbomachinery is affected by various unsteady flow influences, which can significantly impact its efficiency, environment, and operating costs. Therefore, it is crucial to model this flow unsteadiness as accurately as possible to minimize mechanical fatigue and maximize the efficiency of rotating machinery. This way, we can predict performance, detect unstable operating conditions, and identify noise and vibration sources early in the design phase.

To simulate the aerodynamics of compressors and turbines, various methods have been developed, ranging from pseudo-steady to fully unsteady methods. Frequency domain methods, which utilize the spatial and temporal periodicity of the flow to characterize the strong row interactions typical of multi-stage machines, are a special branch of these methods.

In this 30-minute CadenceTECHTALK, we will explain the theory behind the frequency domain approach and discuss different methods available in the literature, including the non-linear method and the harmonic balance method. We will then showcase the non-linear harmonic method on a NASA SDT fan, using Cadence's Fidelity CFD software.

NLH method implemented on turbomachinery clocking effects