TY - JOUR
T1 - Dynamic response of density-stratified fluid in a submarine rectangular trench
AU - Wu, Han Lun
AU - Hsiao, Shih Chun
AU - Hsu, Wen Yang
AU - Yang, Ray Yeng
AU - Hwung, Hwung Hweng
N1 - Funding Information:
This research was supported by the National Science Council, Taiwan, R.O.C . under grants NSC 101-2628-E-006-015-MY3 , NSC 102-3113-P-006-005 , NSC 103-2911-I-006-302 , MOST 103-2221-E-006-229-MY3 and the Open Fund from the State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University (SKHL1308). This research was, in part, supported by the Ministry of Education, Taiwan, R.O.C . The Aim for the Top University Project to the National Cheng Kung University (NCKU).The authors would like to thank Tainan Hydraulics Laboratory (THL) for assistance with the experiments and Prof. T. R. Wu for assistance with the numerical model.
Publisher Copyright:
© 2014 International Association for Hydro-environment Engineering and Research, Asia Pacific Division.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - Interfacial waves under various wave conditions are numerically and experimentally investigated within a submarine rectangular trench. The three-dimensional numerical model Truchas is employed to trace the free surface and the interfacial motion using the volume of fluid method. The free surface and interfacial motion are measured using a CCD camera to validate the model. Both the numerical and experimental results show two types of interfacial motion, namely, partial standing wave patterns and traveling wave patterns. The numerical model is then employed to study the mechanisms of the different modes of interfacial motions (partial standing/traveling waves) and their corresponding amplification factors (external/internal modes). It is shown that the partial standing wave patterns are easily generated when the motion of the surface waves is 180° out of phase at the two sides of the trench. However, the existence of partial standing wave patterns does not mean partial standing internal waves occur. The partial standing internal waves are triggered as internal wave wavelengths reach resonant condition. Furthermore, the ratio of the interface wave height to the surface wave height decreases with wave nonlinearity, suggesting that the nonlinear effect may significantly change the interfacial wave motion. Finally, it is found that the excited pairs of counter-rotating vortices around the interfacial wave can induce a large velocity in the lower layer for the internal mode, indicating that bottom erosion can be enhanced in this manner.
AB - Interfacial waves under various wave conditions are numerically and experimentally investigated within a submarine rectangular trench. The three-dimensional numerical model Truchas is employed to trace the free surface and the interfacial motion using the volume of fluid method. The free surface and interfacial motion are measured using a CCD camera to validate the model. Both the numerical and experimental results show two types of interfacial motion, namely, partial standing wave patterns and traveling wave patterns. The numerical model is then employed to study the mechanisms of the different modes of interfacial motions (partial standing/traveling waves) and their corresponding amplification factors (external/internal modes). It is shown that the partial standing wave patterns are easily generated when the motion of the surface waves is 180° out of phase at the two sides of the trench. However, the existence of partial standing wave patterns does not mean partial standing internal waves occur. The partial standing internal waves are triggered as internal wave wavelengths reach resonant condition. Furthermore, the ratio of the interface wave height to the surface wave height decreases with wave nonlinearity, suggesting that the nonlinear effect may significantly change the interfacial wave motion. Finally, it is found that the excited pairs of counter-rotating vortices around the interfacial wave can induce a large velocity in the lower layer for the internal mode, indicating that bottom erosion can be enhanced in this manner.
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U2 - 10.1016/j.jher.2014.12.004
DO - 10.1016/j.jher.2014.12.004
M3 - Article
AN - SCOPUS:84922369481
SN - 1570-6443
VL - 9
SP - 61
EP - 80
JO - Journal of Hydro-Environment Research
JF - Journal of Hydro-Environment Research
IS - 1
ER -