Marine Hydrodynamics

To find the most suitable trim angle for a planing hull, as a high-speed marine craft, is not an easy task. The right trim angle yields the best performance of a planing hull. It is the main task of this work to develop and provide proposed design contours for the best planing hull trim angles. These trim angles should yield minimum total drag and keep the hull off dynamic-instability regime (porpoising), at different speed ranges. This has been accomplished through hydrodynamic investigation of planing hull performance at different trim angles and speed ranges. In the present work, hydrodynamic equilibrium of planing hull has been considered. In addition, new hydrodynamic applications of transom flap, longitudinal shifting of weights, and proposed wind spoiler have been introduced as trim controlling devices. These applied devices improve and optimize the control of planing hull trim angles at different speeds, aiming to achieve best possible planing hull performance. To perform an optimization process and develop design contours for the best operating trim, three phases of computer program, have been specially designed. Applications of the present analysis have been performed on specific planing hull geometry. Useful and encouraging, results for the best trim angles operating regimes have been determined for different hull designs at different ranges of speed.

The resistance and the hydrodynamic characteristics of the Sprint Master canoe that is used in Universiti Teknologi Malaysia (UTM) have been studied at different speeds using Computational Fluid Dynamics (CFD) method. The resistance of the canoe at different speeds has been measured in UTM marine technology center (MTC). The finite volume code Ansys CFX has been used for carrying out the numerical simulations for the hull form of the canoe at the same experimental speeds. The Volume of Fluid method (VOF) has been used with Ansys CFX for capturing the free surface flow around the canoe hull at the same experimental speeds. The Shear Stress Transport (SST) turbulence model has been used in the RANSE code. The grid generator ICEM CFD has been used for building the grids for the RANSE code solver. The numerical results compare very well with the experimental results at the different speeds.

Hydro-geology (hydro- meaning water, and -geology meaning the study of the Earth) is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust (commonly in aquifers). The term hydrology is often used interchangeably. Some make the minor distinction between a hydrologist or engineer applying themselves to geology (hydrology), and a geologist applying themselves to hydrology (hydro geology).Hydrogeology is an interdisciplinary subject; it can be difficult to account fully for the chemical, physical, biological and even legal interactions between soil, water, nature and society. The study of the interaction between groundwater movement and geology can be quite complex. Groundwater does not always flow in the subsurface down-hill following the surface topography; groundwater follows pressure gradients (flow from high pressure to low) often following fractures and conduits in circuitous paths. Taking into account the interplay of the different facets of a multi-component system often requires knowledge in several diverse fields at both the experimental and theoretical levels. The following is a more traditional introduction to the methods and nomenclature of saturated subsurface hydrology, or simply the study of ground water content.Hydrogeology, as stated above, is a branch of the earth sciences dealing with the flow of water through aquifers and other shallow porous media (typically less than 450 m or 1,500 ft below the land surface.) The very shallow flow of water in the subsurface (the upper 3 m or 10 ft) is pertinent to the fields of soil science, agriculture and civil engineering, as well as to hydrogeology. The general flow of fluids (water, hydrocarbons, geothermal fluids, etc.) in deeper formations is also a concern of geologists, geophysicists and petroleum geologists. Groundwater is a slow-moving, viscous fluid (with a Reynolds number less than unity); many of the empirically derived laws of groundwater flow can be alternately derived in fluid mechanics from the special case of Stokes flow (viscosity and pressure terms, but no inertial term). The mathematical relationships used to describe the flow of water through porous media are the diffusion and Laplace equations, which have applications in many diverse fields. Steady groundwater flow (Laplace equation) has been simulated using electrical, elastic and heat conduction analogies. Transient groundwater flow is analogous to the diffusion of heat in a solid, therefore some solutions to hydrological problems have been adapted from heat transfer literature.Traditionally, the movement of groundwater has been studied separately from surface water, climatology, and even the chemical and microbiological aspects of hydrogeology (the processes are uncoupled). As the field of hydrogeology matures, the strong interactions between groundwater, surface water, water chemistry, soil moisture and even climate are becoming more clear.For example: Aquifer drawdown or overdrafting and the pumping of fossil water may be a contributing factor to sea-level rise

El complejo sedimentario isla barrera – laguna litoral salina de Sauca localizado en la costa nororiental del estado Falcón (11º23'22 " – 11º27'39 " L N y 68º49'33 " – 68º55'05 " L O), constituye un ejemplo de un sistema sedimentario desarrollado en un medio costero, cuya dinámica depositacional es controlada por la confluencia de factores morfodinámicos climáticos, continentales y marinos, lo cual le confiere un carácter de ambiente transicional. El estudio de estos factores (clima, drenaje superficial, mareas, oleaje y corriente litoral) se basó en el análisis de datos preexistentes, mediciones y cálculos sobre cartas topográficas a escala 1:25.000, y mediciones y observaciones de campo. El área de interés se enmarca dentro de un sector costero de tipo climático semi-húmedo a semi-árido de acuerdo con la clasificación de Thornwaite, y Awi (clima tropical de sabana) según la clasificación de Köeppen, con una velocidad media del viento de 20,9 Km/h. El sistema de microcuencas de drenaje de la salina de Sauca es de pequeñas dimensiones, con cursos de agua de cortos recorridos, régimen efímero y baja densidad de drenaje. Las mareas son de tipo mixtas y de rango micromareal (26,36 cm), con muy poca influencia en la morfodinámica del área. El oleaje es de alta energía, con variaciones a lo largo de la bahía de Boca de Sauca, que reflejan la influencia de la forma y orientación de la costa en la dirección original de éste, y establecen variaciones granulométricas en los sedimentos de la isla barrera en sentido longitudinal. La corriente litoral realiza un transporte efectivo a lo largo de la línea de costa en sentido este – oeste, generada por la acción del oleaje, con poca influencia en el área protegida de la bahía donde se ubica la boca de la laguna, por efecto de la refracción del oleaje, que modifica el ángulo de incidencia del mismo sobre la costa.