Understanding the basics of Fourier harmonic modeling applied to turbomachinery unsteady flows the flow field in turbomachinery is dominated by inherently unsteady flow features such as blade-row interactions, blade vibration, inlet flow or thermal distortions. A proper understanding of these features is essential for an accurate prediction of the machine performances at design and off-design conditions. Traditional time-domain unsteady methods are able to simulate the physics in turbomachinery but are prohibitively expensive to be fully integrated into the product design phase. NUMECA's Nonlinear Harmonic method (NLH) is a great alternative to conventional approaches by providing high fidelity results at a fraction of the computational cost. This webinar will cover the basics of the NLH method applied to turbomachinery unsteady flows. We will outline how the basic characteristic of flow periodicity in turbomachinery is used as a tool for achieving from 100 to 1000 times faster simulations when compared to full-unsteady methods. CFD solutions of real turbomachinery test cases using steady-state, unsteady time domain and NLH solution methods are showcased and discussed.