Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio
Direct numerical simulation; Fluid mechanics; Gravitation; Gravity waves; Numerical models; Reynolds number; Vortex flow; Critical regimes; Gravity currents; Kelvin-Helmholtz; Size and shape; Strong stratification; Subcritical flow; Supercritical flow; Weak stratification; Aspect ratio
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Australasian Fluid Mechanics Society
2023
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my.uniten.dspace-239402023-05-29T14:53:20Z Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio Lam W.K. Chan L. Hasini H. Ooi A. 57205240468 57139456500 6507435998 7005905452 Direct numerical simulation; Fluid mechanics; Gravitation; Gravity waves; Numerical models; Reynolds number; Vortex flow; Critical regimes; Gravity currents; Kelvin-Helmholtz; Size and shape; Strong stratification; Subcritical flow; Supercritical flow; Weak stratification; Aspect ratio Direct numerical simulations (DNSs) of two-dimensional stratified gravity current are carried out using OpenFOAM. Three different aspect ratios, h0/l0 (where h0 is the height of the dense fluid and l0 is the length of the dense fluid) are simulated with stratification strength, S=0.2, 0.5, and 0.8. Reynolds number is kept constant at Re=4000. For the equivalent h0/l0 ratio, the stratification strength reduces the front velocity, uf and results in a shorter front location, xf-l0. Stratification strength has a strong effect on the size and shape of the gravity current. Gravity current with aspect ratio, h0/l0 of 0.25 propagating in the stratified ambient of S=0.2 and 0.5 experienced two acceleration phases. Qualitiative analysis of contours ranging from subcritical to supercritical flow in comparison to the flow structures was presented in this study. Subcritical flow was smooth and minimal vortices formed in the head of the gravity current was obtained in all the cases with strong stratification strength, S=0.8. Supercritical flow occurs in weak stratification with h0/l0=1 and 4. Strong vortices formed in the head of the gravity current followed by Kelvin-Helmholtz (K-H) billows at the back of the head. The propagation of the internal waves was faster than the gravity current flow in the subcritical regime. Case h0/l0=4 with S=0.5 had the Froude number closest to the critical regime (Fr=0.324 ? 1/?) and can be deemed to be in the critical regime. � 2018 Australasian Fluid Mechanics Society. All rights reserved. Final 2023-05-29T06:53:19Z 2023-05-29T06:53:19Z 2018 Conference Paper 2-s2.0-85084096977 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084096977&partnerID=40&md5=03e1705d65a505e05b047afd60ce9eb9 https://irepository.uniten.edu.my/handle/123456789/23940 Australasian Fluid Mechanics Society Scopus |
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| description |
Direct numerical simulation; Fluid mechanics; Gravitation; Gravity waves; Numerical models; Reynolds number; Vortex flow; Critical regimes; Gravity currents; Kelvin-Helmholtz; Size and shape; Strong stratification; Subcritical flow; Supercritical flow; Weak stratification; Aspect ratio |
| author2 |
57205240468 |
| author_facet |
57205240468 Lam W.K. Chan L. Hasini H. Ooi A. |
| format |
Conference Paper |
| author |
Lam W.K. Chan L. Hasini H. Ooi A. |
| spellingShingle |
Lam W.K. Chan L. Hasini H. Ooi A. Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| author_sort |
Lam W.K. |
| title |
Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| title_short |
Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| title_full |
Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| title_fullStr |
Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| title_full_unstemmed |
Direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| title_sort |
direct numerical simulation of two-dimensional stratified gravity current flow with varying stratification and aspect ratio |
| publisher |
Australasian Fluid Mechanics Society |
| publishDate |
2023 |
| _version_ |
1806427370657153024 |
| score |
13.214268 |