Showing papers by "Vallam Sundar published in 2017"

Integration of wave energy and other marine renewable energy sources with the needs of coastal societies

Abstract: Marine renewable energy has the potential to solve both the energy-security and coastal-protection problems affecting coastal societies. In this article, the potential benefits arising from the com...

Reassessment of tidal energy potential in India and a decision-making tool for tidal energy technology selection

Abstract: Oceans have significant renewable energy options to provide environmental friendly and clean energy. Technology for ocean energy systems and the feasibility for extraction of the same is an importa...

Ocean Wave Mechanics: Applications in Marine Structures

Abstract: It is believed that Oceans constitute about 70% of the surface of the Earth and about 97% of the water content of the Earth belongs to the oceans. It is believed that about 1% is fresh water, and 2–3% is in the form of glaciers and ice caps. The ocean is rich in natural living and non-living resources. In order to explore and exploit the vast non-living resources like oil, gas and minerals from beneath the ocean floor, a variety of structures are needed to be designed and installed. The perennial instability of shorelines leading to coastal erosion along certain stretches of the coast and the natural coastal hazards like storm surge, tsunami, etc., necessitate protection measures mostly in the form of structures like seawalls, groins, offshore detached breakwaters, etc. constructed along or near the coast. One major developmental activity along the coast is the development of harbors by constructing breakwaters. The major environmental parameters that need to be considered in the design of all the aforementioned different types of structures are the wind, waves, tides and currents. Among these, although the loads due to waves dominate and dictate the design of structures in the marine environment, the characteristics of other parameters are also essential.

Stability of micro-tidal inlets along coastlines dominated by littoral drift

Abstract: The dynamics of micro-tidal inlets is quite complicated as their stability is controlled both by the littoral drift and the tidal range. Thus the process of assessing their stability is not well understood and quite challenging. This paper brings out the process of assessing the stability aspects of inlets using numerical codes. The equilibrium between the longshore transport rate and spring tidal prism ensures the stability of inlet between ocean and estuary. However, any disturbance to this equilibrium leads to the closure of the inlets. The active movement of sediments in the surf zone are due to the long shore velocity, the driving force for the littoral drift, which is obtained with the application of time domain model, FUNWAVE, a public domain software. With the driving force thus obtained, the long shore transport is then estimated through empirical relations from which, the stability of the inlet is assessed. The spring tidal prism is the discharge of the flow entering into the ocean from inlets/estuaries. The flow velocity is determined by the application of shallow water model. The input data for the nearshore circulation due to waves and currents are mostly measured from the field. For the current study, the Kondurpalem inlet(14001′07″N, 80009′24″E)along the East coast of Indian peninsula is investigated and its seasonal variation is assessed. The stability state of the inlet is re-assessed by providing necessary training works. The stability of the trained inlet is found to be more stable and the minimum depth and width to be maintained in the inlet gorge can be established through this process.

Stability of a micro-tidal inlet using semi-numerical approach:

Abstract: Tidal inlets get disconnected depending on the seasons due to the formation of sand bars near its mouth are termed as “seasonally open tidal inlets.” These inlets are usually small of width of about 100 m and occur in micro-tide (tidal range not exceeding 1 m). Since the east coast of India experiences a net littoral drift of up to about 0.8 Mm3/annum, which is one of the largest in magnitudes that needs to be considered in the analysis of modeling of the sand bar formation and the associated phenomena. Kondurpalem inlet situated along the South east coast of India is considered as a case study. A frequency domain wave model (STeady-state spectral WAVE) has been used to compute the nearshore wave climate. The wave-induced currents have been obtained, and the longshore sediment transport rate is obtained through empirical relations. The tidal prism is found from measured depth and tidal velocity by solving shallow water equations. The stability of the inlet is investigated by applying the criteria develope...