HPC and CFD in the marine industry: past, present and future

This paper explores the use of Computational Fluid Dynamics (CFD) applications on High Performance Computing (HPC) platforms from the perspective of a user engaged in Naval Architecture research. The paper will consider the significant limitations which were imposed on research boundaries prior to present HPC capabilities, how this impacted development in the field and the implications for industry. One particular example is the costly experimental testing which, due to resource constraints, is generally restricted to model scale. It will then present an overview of the numerical simulation capabilities using current HPC performance and capability. With the increase of computational power and capacity, CFD simulations are proving to be more accurate and reliable. Being relatively cheaper and more time efficient, numerical methods are becoming the preferred choice within the industry compared to traditional experimental tests. Nevertheless, certain experimental procedures cannot be numerically replicated with the current levels of computational capacity. The future needs and challenges of research and development will be outlined and discussed, highlighting the significant impact exascale computing will have in the field

An investigation of the effect of biomimetic tubercles on a flat plate

This paper describes the investigation, by means of Computational Fluid Dynamics (CFD), of the effect of biomimetic tubercles on the hydrodynamics of a fully submerged flat plate. The application of these tubercles takes inspiration from the features of the humpback whale (Megaptera Novaeangliae). These huge marine mammals are capable of quick and agile movements in the water, despite their bulky bodies. Researchers investigated the causes of this ability by studying some peculiar somatic characteristics of these animals, in particular the tubercles on the leading edge of their pectoral fins. These tubercles were applied in the form of sinusoidal perturbations of the leading edge of wing profiles and foils, and they proved to cause a positive effect on the overall performance. The aim of this paper is to investigate another type of tubercles, which appear in the shape of bumps on the whales head. The effect of these tubercles has not been studied yet, and this paper presents a study on the fundamental phenomena they generate in the water flowing on the surface of a flat plate. The tubercles are modelled as axisymmetric sinusoidal bumps placed on the flat plate. Different combinations of these tubercles are studied, in order to assess what the effect of a single tubercle is, and how more tubercles interact when they are placed closed to each other, in different configurations (number of tubercles and relative position). In addition, a systematic study of the effect of a single row of tubercles spanning perpendicularly to the flow is carried out. The tubercles change systematically in amplitude and position along the plate. One further objective of this paper is to investigate if an optimised application of the biomimetic tubercles can lead to a drag reduction for the flat plate. Preliminary simulations show that the rows of tubercles interact with the boundary layer by modifying the pressure distribution, velocity and direction of the flow. The tubercles appear to generate vortices that are similar to those created by sinusoidal tubercles on the leading edge of foils, which tend to thin the boundary layer. A change in the total drag of the plate with tubercle is also noticeable, which even decreases from the baseline (flat plate with no tubercles), at certain combinations of position and tubercle amplitude

Design specification, commission and calibration of the University of Strathclyde's Fully Turbulent Flow Channel (FTFC) facility

Measurements in the Fully Turbulent Flow Channel (FTFC) are presented for Reynolds number up to 3.3∙10^5, based on the mean bulk velocity and the channel height. The FTFC is a new experimental facility recently installed at the Department of Naval Architecture, Ocean and Marine Engineering of the University of Strathclyde. It is a high aspect ratio flow channel with a three-meter-long testing section, designed for the indirect measurement of the drag caused by surface characteristics. The main advantage of this channel is that the measurements of the pressure drop along the test section can be combined with laser-based boundary layer measurement techniques such as LDA, PIV, etc. The present work focuses on the design features and the calibration of the new experimental facility, with hydraulically smooth control panels produced on purpose. The interest in these data originates from the fact that channel flow serves as a reference flow for varying special surface structures, such as fouling control coatings, as well as some drag reduction mechanisms such as riblets, dimples, tubercles, in the presence of some biofouling types