Numerical and theoretical investigation of pulsatile turbulent channel flows
2016 (English)In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 792, 98-133 p.Article in journal (Refereed) PublishedText
A turbulent channel flow subjected to imposed harmonic oscillations is studied by direct numerical simulation (DNS) and theoretical models. Simulations have been performed for different pulsation frequencies. The time- and phase-averaged data have been used to analyse the flow. The onset of nonlinear effects during the production of the perturbation Reynolds stresses is discussed based on the DNS data, and new physical features observed in the DNS are reported. A linear model proposed earlier by the present authors for the coherent perturbation Reynolds shear stress is reviewed and discussed in depth. The model includes the non-equilibrium effects during the response of the Reynolds stress to the imposed periodic shear straining, where a phase lag exists between the stress and the strain. To validate the model, the perturbation velocity and Reynolds shear stress from the model are compared with the DNS data. The performance of the model is found to be good in the frequency range where quasi-static assumptions are invalid. The viscoelastic characteristics of the turbulent eddies implied by the model are supported by the DNS data. Attempts to improve the model are also made by incorporating the DNS data in the model.
Place, publisher, year, edition, pages
Cambridge University Press, 2016. Vol. 792, 98-133 p.
turbulence simulation, turbulent boundary layers, wave-turbulence interactions
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-184951DOI: 10.1017/jfm.2016.73ISI: 000371400400007ScopusID: 2-s2.0-84959386828OAI: oai:DiVA.org:kth-184951DiVA: diva2:917821
FunderSwedish Research Council
QC 201604072016-04-072016-04-072016-08-16Bibliographically approved