SIMULATION OF UNSTEADY TURBOMACHINERY FLOWS USING AN IMPLICITLY COUPLED NONLINEAR HARMONIC BALANCE METHOD
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A nonlinear harmonic balance method for the simulation of
turbomachinery flows is presented. The method is based on representing
an unsteady, time periodic flow by a Fourier series
in time and then solving a set of mathematically steady-state
equations to obtain the Fourier coefficients. The steady-state
solutions are stored at discrete time levels distributed throughout
one period of unsteadiness and are coupled via the physical
time derivative and at periodic boundaries. Implicit coupling between
time levels is achieved in a computationally efficient manner
through approximate factorization of the linear system that
results from the discretized equations.
Unsteady, rotor-stator interactions are performed to validate
the implementation. Results based on the harmonic balance
method are compared against those obtained using a full
unsteady, time-accurate calculation using moving meshes. The
implicitly coupled nonlinear harmonic balance method is shown
to produce a solution of reasonable accuracy compared to the
full unsteady approach but with significantly less computational
cost.

Author Name: 
Jonathan M. Weiss
Venkataramanan Subramanian
Kenneth C. Hall
Author Company: 
CD-adapco
Department of Mechanical Engineering and Materials Science, Duke University
Products: 
Conference Location: 
Vancouver
Conference Proceeding PDF: 
Conference Date: 
Monday, June 6, 2011
Conference Name: 
ASME Turbo