Repeatability and Two-Dimensionality of Model Scale Sloshing Impacts

Canonical test cases for sloshing wave impact problems are pre-sented and discussed. In these cases the experimental setup has been simpli?ed seeking the highest feasible repeatability; a rectangular tank subjected to harmonic roll motion has been the tested con?guration. Both lateral and roof impacts have been studied, since both cases are relevant in sloshing assessment and show speci?c dynamics. An analysis of the impact pressure of the ?rst four impact events is provided in all cases. It has been found that not in all cases a Gaussian ?tting of each individual peak is feasible. The tests have been conducted with both water and oil in order to obtain high and moderate Reynolds number data; the latter may be useful as simpler test cases to assess the capabilities of CFD codes in simulating sloshing impacts. The re-peatability of impact pressure values increases dramatically when using oil. In addition, a study of the two-dimensionality of the problem using a tank con?guration that can be adjusted to 4 di?erent thicknesses has been carried out. Though the kinemat-ics of the free surface does not change signi cantly in some of the cases, the impact pressure values of the ?rst impact events changes substantially from the small to the large aspect ratios thus meaning that attention has to be paid to this issue when reference data is used for validation of 2D and 3D CFD codes

Benefits of using a Wendland Kernel for free-surface flows

The aim of this paper Is lo discuss the influence of the selection of the interpolation kernel in the accuracy of the modeling of the internal viscous dissipation in Tree surface Hows, Simulations corresponding to a standing wave* for which an analytic solution available, are presented. Wendland and renormalized Gaussian kernels are considered. The differences in the flow pattern* and Internal dissipation mechanisms are documented for a range of Reynolds numbers. It is shown that the simulations with Wendland kernels replicate the dissipation mechanisms more accurately than those with a renormalized Gaussian kernel. Although some explanations are hinted we have Tailed to clarify which the core structural reasons for Mich differences are

Nuevas herramientas de diseño de formas de buques basadas en códigos de flujo potencial

El objetivo de la tesis doctoral es la obtención de un código de flujo de potencial de la resistencia por la formación de olas de buques. Se utiliza un método de paneles con condición de contorno lineal en la superficie libre. En el trabajo se presta atención especial al caso problemático de la popa de espejo. Los programas se han validado con resultados experimentales. Se crea una herramienta de diseño con un gran valor para comparar la bondad de las formas de buques

Safety and operability of small fishing vessels: study of a series of stability-related accidents

The intact stability of five small Spanish fishing vessels with ages between 3 and 8 years old which sunk in stability related accidents between 2004 and 2007 is compared to the stability of the fishing vessels which were retired from service to build those. The seakeeping performance of both sets of vessels is also compared. The differences found between the results obtained by the two methods have been analyzed. The suitability of seakeeping methods to assess stability performance is discussed

Implementación European Credit Transfer System en un curso de Programación en Ingeniería = European Credit Transfer System implementation in an Introduction to Programming Course for a Mechanical Engineering Degree

Los autores documentan en este artículo el proceso de adaptación a una metodología acorde con los créditos ECTS dentro de una asignatura de introducción a la Programación de ordenadores para ingenieros, equiparable a la que existe en los primeros cursos de las ingenierías superiores de corte más industrial (Ingeniería Industrial, Ingeniería de Caminos, Canales y Puertos, Ingeniería Aeronáutica, Ingeniería de Minas e Ingeniería Naval y Oceánica). Para ese proceso de adaptación se han tomado como referencia los modelos de madurez del proceso (CMM) de Ingeniería del Software y se han adaptado estos modelos, sustituyendo los procesos de elaboración de software por los formativos. Se documenta el proceso tratando de que éste sea repetible y sobre todo evaluable por agentes externos. Mientras que la mayoría de las experiencias de adaptación se centran en cuestiones relativas a la cuantificación del esfuerzo realizado por los estudiantes, en este caso se ha querido aprovechar esta oportunidad para realizar una transformación metodológica profunda, incorporando la evaluación a toda la intervención educativa. Se describe con detalle el tipo de evaluación realizada, la cual contempla la realización de un portafolio, el trabajo en grupo, la ponderación explícita de la participación y que no excluye por principio la posibilidad de aprobar sólo mediante un examen final. Se presentan resultados comparativos respecto a cursos anteriores, y correlaciones entre la evaluación ECTS y la basada simplemente en el examen. Los resultados son interesantes y sugieren que estamos cerca de completar el nivel Definido en la escala CMM. In this article, a process of adaptation to an ECTS-type methodology is documented in the context of an introductory programming course for mechanical engineers, similar to the one that exists in the initial years of more industrially-oriented engineering degrees (civil engineering, construction engineering, aeronautical engineering, mining engineering, and naval architecture and offshore engineering). For this adaptation process,Capability Maturing Models (CMM) from Software Engineering have been taken as moulds, adapting them by substituting software elaboration processes by pedagogical ones.The process is documented in a way that can be replicated and assessed by external consultants.While the majority of the ECTS adaptation experiences focus on quantifying the students' efforts, in this case, the authors have taken advantage of this opportunity to perform a profound methodological transformation, incorporating the assessment to the whole learning-teaching activity. The assessment technique is described in detail and it comprises the compiling of a portfolio, group work and explicit student participation assessment. It does not exclude on principle the possibility of passing simply via a final exam. Comparative results with previous academic years are presented, as well as correlations between ECTS assessment and marks based on the final exam. Results are interesting, suggesting we are not far from completing the CMM defined level

Reynolds number and Shallow Depth Sloshing

The dependence on the Reynolds number of shallow depth sloshing flows inside rectangular tanks subjected to forced harmonic motion is studied in this paper with weakly compressible SPH. We are interested in assessing the in fluenceof viscous effects on the dynamics of shallow depth sloshing flows by using an SPH solver and by comparing with a Navier-Stokes level-set solver results. The goal of trying to model these viscous flows is compromised by the resolution requested due to their Reynolds number, if boundary layer effects are to be modeled. The convenience and feasibility of the implementation of free-slip and no-slip boundary conditions is also discusse

Modeling of Free Surface Flows with Elastic Bodies Interactions

In this paper, a series of new fluid and structure interactions test cases with strong free surface effects are presented and computations of such flows with the Particle Finite Element Method (PFEM) (Idelsohn, Oiiate, Del Pin and Calvo, 2006) are documented. The structures object of study are elastic cantilever bars clamped inside sloshing tanks subjected ro roll motion. The possibilities of PFEM for the coupled simulation of moderately violent free surface flows interacting with elastic bodies are investigated. The problem can be described as the coupling of a sloshing flow with an easily deformable elastic body. A series of experiments designed and executed specifically for these tests are also described. The experiments comprise cases with different liquid height and liquids of different viscosity. The aim is to identify canonical benchmark problems in FSI (Fluid and Structure Interactions), including free surfaces, for future comparisons between different numerical approaches