Direct numerical simulation of turbulent flow and heat transfer within a spanwise-rotating elliptical pipe
| dc.contributor.author | Hurtado Rosas, Rafael | |
| dc.contributor.examiningcommittee | Tachie, Mark F. (Mechanical Engineering) Zhang, Qiang (Biosystems Engineering) | en_US |
| dc.contributor.supervisor | Wang, Bing-Chen (Mechanical Engineering) | en_US |
| dc.date.accessioned | 2021-05-06T15:19:50Z | |
| dc.date.available | 2021-05-06T15:19:50Z | |
| dc.date.copyright | 2021-05-03 | |
| dc.date.issued | 2021-05-03 | en_US |
| dc.date.submitted | 2021-05-03T14:34:26Z | en_US |
| dc.date.submitted | 2021-05-06T14:00:13Z | en_US |
| dc.degree.discipline | Mechanical Engineering | en_US |
| dc.degree.level | Master of Science (M.Sc.) | en_US |
| dc.description.abstract | In this thesis, the effects of spanwise system rotation on turbulent flow and heat transfer in an elliptical pipe are investigated using direct numerical simulation (DNS). To study the effects of system rotation on the heat and fluid flows, seven rotation numbers have been tested for 0.25 ≤ Ro τ ≤ 24.0. The results of these rotating flow cases are compared with those of the non-rotating flow case (Ro τ = 0). The pipe length has been extended to L z = 20πb to ensure that the most energetic eddy motions are well captured on the axial direction in the DNS. The results show that large counter-rotating vortical structures appear in the cross-stream plane in response to system rotation, which have profound influence on the turbulence statistics. It is further observed that laminarization occurs on the suction side of the pipe and spreads towards its pressure side with an increasing rotation number. At a moderate rotation number (Ro τ = 8.0), the Coriolis term of the transport equation of Reynolds stresses dominates turbulence kinetic energy transfer from axial to the wall-normal Reynolds stress components. Similarly, the Coriolis term in the transport equation of turbulence heat fluxes transfers turbulent scalar energy from <w'θ'> to <v'θ'>, and dominates the turbulent production term at a moderate rotation number. The influences of the Coriolis force on the turbulent transport of momentum and thermal energy have been analyzed in both physical and spectral spaces through analyses of the first- and second-order statistical moments, including the mean velocities and temperatures, Reynolds shear stresses, turbulent heat fluxes, pre-multiplied spectra of the velocity and temperature fluctuations, and coherent flow and thermal structures. | en_US |
| dc.description.note | October 2021 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/35498 | |
| dc.language.iso | eng | en_US |
| dc.rights | open access | en_US |
| dc.subject | Turbulence, Rotating flow, Elliptical pipe flow, Turbulent heat transfer | en_US |
| dc.title | Direct numerical simulation of turbulent flow and heat transfer within a spanwise-rotating elliptical pipe | en_US |
| dc.type | master thesis | en_US |