Abstract

The recent requirements of Spanish regulations and directives, on their turn based on European directives, have led to the development of a new two dimensional open channel flow modelling tool. The tool, named Iber, combines a hydrodynamic module, a turbulence module and a sediment transport module, and is based in the finite volume method to solve the involved equations. The simulation code has been integrated in a pre-process and post-process interface based on GiD software, developed by CIMNE. The result is a flow and sediment modelling system for rivers and estuaries that uses advanced numerical schemes, robust and stable, which are especially suitable for discontinuous flows taking place in torrential and hydrologically irregular rivers.

Abstract

This research focuses on identifying the most important stern shape aspects, with regard to resistance and propulsion power, of inland ships. Such information should help designers to determine which hull form aspect to adjust in case design requirements need them to do so. The information is obtained by firstly conducting a large series of CFD calculations, using the PARNASSOS code, for systematically varied inland ships. Next, response surface technologies are used to identify the most important aspects. This is done by sequentially adding and/or removing parameters from the response surface in order to find the combination of parameters that explains the majority of the variance in the performance data for the tested hull forms. Finally, an optimization algorithm is used to determine the optimal hull forms for varying displacement, showing which parameters should be adjusted preferably in order to increase (or decrease) ship displacement. This, specifically, should aid designers in making the trade-off between displacement (or cargo capacity) and energy consumption.

Abstract

This research focuses on identifying the most important stern shape aspects, with regard to resistance and propulsion power, of inland ships. Such information should help designers to determine which hull form aspect to adjust in case design requirements need them to do so. The information is obtained by firstly conducting a large series of CFD calculations, using the PARNASSOS code, for systematically varied inland ships. Next, response surface technologies are used to identify the most important aspects. This is done by sequentially adding and/or removing parameters from the response surface in order to find the combination of parameters that explains the majority of the variance in the performance data for the tested hull forms. Finally, an optimization algorithm is used to determine the optimal hull forms for varying displacement, showing which parameters should be adjusted preferably in order to increase (or decrease) ship displacement. This, specifically, should aid designers in making the trade-off between displacement (or cargo capacity) and energy consumption.

Abstract

The modification of the shallow water icing model to handle de-icing phenomenon is the main focus of this study. As stated in the original model [1], the runback water is modeled utilizing a lubrication assumption for the water film velocity profile. A constant film temperature Tf(t,x) is then calculated under the thin-film hypothesis. Unlike the simplified icing model, the temperature field within the ice layer Tice(t,x,z) is no longer assumed to be constant. Instead, a temperature profile is utilized, enabling the generation of a static film on the wall when a heat conduction source term from a resistance is present [2]. A Temperature profile Ts(t,x,z) is also used in the static film layer if the model predicts the occurrence of this state. In the energy equation for both the solid ice and liquid portion of the static water film, transverse transfers are not considered, a 1D heat equation is then resolved. An integral approach and proper boundary conditions are used to close the problem. The validity of the integral method deteriorates as the thickness over which vertical integration is performed increases. To avoid this problem, a multi-layer approach is proposed. The thickness of the ice block is then divided into three layers of identical thickness. The purpose of this study is to offer a straightforward and robust method suitable for conducting industrial test cases. The model will first be introduced, followed by a description of the numerical approach. Subsequently, validation test cases will be conducted. Realistic de-icing scenarios will then be designed to evaluate the model [3]. Additionally, non uniform roughness effects will be examined.