Numerical study of the Stokes layer in oscillating channel flow
(English)Manuscript (preprint) (Other academic)
Oscillating turbulent channel flows present particular physics that proves to be particularly difficult to understand. In this paper, a case where the amplitude of the oscillations at the center of the channel is approximately 15% of the mean velocity and the dimensionless angular forcing frequency is 0.01 was studied using several numerical methods. DNS was performed to serve as reference to which the results from an LES were compared. The LES data was post-processed using both phase averaging and the more recent dynamic mode decomposition (DMD), which extracts coherent structures based on their frequency. It was found that the DMD is not able to extract faint harmonic components of the oscillations, which have been observed with phase averaging and Fourier transforms. It is, however, able to extract accurate profiles of the mean and forcing frequency quantities. Compared to the DNS, the accuracy of the LES results was similar to analytical models, although no single model gives accurate result for every quantity investigated.
pulsating channel flow, LES, DNS, DMD
Research subject Engineering Mechanics
IdentifiersURN: urn:nbn:se:kth:diva-161407OAI: oai:DiVA.org:kth-161407DiVA: diva2:794522
QS 20152015-03-112015-03-112015-05-26Bibliographically approved