No abstract

The oil and gas industry requires complex subsea infrastructure in order to develop offshore oil and gas fields. Upon installation, these components may encounter high slamming loads, stemming from impact with the water surface. This paper utilises Smoothed Particle Hydrodynamics to quantify these loads on a free-falling object. The investigation is interested in conducting a parameter study and determining the effect of varying simulation parameters on the prediction of slamming event kinematics and forces. The surface impact of a 2D freefalling wedge was simulated, with the results being compared to an experimental investigation. It was found through the parameters that particle resolution and the size of the SPH particle kernel are very important, whilst the diffusion terms do not play an important role. The latter is due to the very transient nature of slamming events, which do not allow sufficient time for diffusion in the domain. The close correlation of numerical and experimental results, along with the robustness and quick set up of SPH slamming simulations, indicate that SPH is a promising method of modelling more complicated slamming problems, which may involve more intricate impacting structures.

A method was developed for measuring the time of flow in an Ubellohde viscometer to an accuracy of 3 ppm. For this purpose the following points were shown to be crucial: (a) use of a thermostat with a long time thermal stability of ±2XIo-4°C ; (b) closing the viscometer off to the outside during all stages of the experiment; (c) adoption of a standard procedure for cleaning and preparing the glass surface; (d) maintenance of the viscometer bulb and capillary always in contact with the fluid by raising level immediately after each experiment; (e) adjustment of the position of the viscometer reproducibly; (f) measurement of the time of flow to within 1 msec. A full description of all parts of the system except the thermostat is given. The thermostat has been described separately. Examples are given illustrating both the accuracy of the technique and the importance of each and all of the above points.This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitationnew.aip.org/termsconditions. Downloaded to IP: