Numerical and analytical models of beach erosion | |
| Author | Doloi, Hemanta Kumar |
| Call Number | AIT Thesis no.WA-94-5 |
| Subject(s) | Numerical analysis Beach erosion |
| Note | A thesis submitted m partial fulfilment of the requirement for the Degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Accurate estimates of beach and dune erosion on the open coast due to the violent storm waves are required for a variety of regulatory and design purposes. But as a first step of engineering approach, a simplified mathematical model which can represent those significant features of the nature is considered to be an appropriate tool. An one-dimensional model has been verified for the cases of dune and beach erosion produced by storm waves and water levels. The model is based on empirical relationships of sediment transport rates proposed by Larson and Kraus (1989) and was used to observe net crossshore sand transport rates and geometric change based on both L WT laboratory data as well as field data. An extensive verification has been done for the prediction of dune erosion during a severe storm based on the data collected at Visakhapatnam port located between Madras and Paradip on the east coast of India. It is found that both foreshore and offshore beach profiles can be simulated satisfactorily for L WT data by using sand diameter 0.22mm and 0.27mm. But in case of field condition, only foreshore beach profiles have been simulated for 0.1 Omm sand diameter and the offshore bar could not be verified due to the lack of information at the offshore end. A new criterion by which the change of beach profiles can be simulated by considering only three transport zones, (Zones II ,III and IV) has been developed based on field conditions. The identity of the plunging point in the field condition was found to be insignificant. A new relationship is used for the calculation of runup height at swash zone in the field condition. Sand diameter and transport rate coefficients are found to have significant influence on bar volume while effect of reflected waves on equilibrium beach profile is not so pronounced. Results of an extensive correlation and regression analysis showed that the normalized sediment volume can be related with different dimensionless breaking wave characteristics such as Hb/L0 , Hb/wT 0 etc. Decay of peak offshore transport rate with the elapse time can be described by an inverse function of maximum transport rate of time for both L WT as well as field conditions. |
| Year | 1994 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Resources Research Engineering (WA) |
| Chairperson(s) | Suphat Vongvisessomjai |
| Examination Committee(s) | Sutat Weesakul ;Imamura, Fumihiko |
| Scholarship Donor(s) | The Government of Denmark |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1994 |