Towards an Accurate and Useful Engineering Theory on Slamming Emanating from Partitioned CU-BEN/OpenFOAM FSI Simulations
Abstract
Slamming loads are important ~secondary~ loads to consider in high speed watercraft of all sizes. Indeed, the monicker of ~secondary~ is quite misleading since, in high speed watercraft, consideration of these loads is of critical importance for safety and satisfactory performance of the hull. Indeed, the American Bureau of Shipping, (ABS), in its HSNC 2007 guide for building and classing naval craft, has called out slamming loads as the single most important consideration when proportioning hull scantlings within such design contexts. In the case of high speed monohulls, it is bottom slamming that is most at issue, while in high speed multihulls, it is wetdeck slamming that is most concerning.In spite of the requirement for deep insight into slamming loads for the successful fielding of high speed naval vessels, current design approaches are limited to experimental and theoretical work, whose scope was restricted to small planing hulls, that was carried out in the 60 s and 70 s. Part of the reason for this paucity in experimental and theoretical work related to slamming has to do with the extremely small spatiotemporal scales that are involved in describing this phenomenon, in a manner that maintains reasonable fidelity with the real world. This practical spatiotemporal scale-related challenge has hampered theoretical understanding as a result of very limited high quality experimental observations and quantitative data. Additionally, the nature of the slamming phenomenon, itself (i.e. small, distributed spatial scales that are acquired at very high frequencies) makes empirical studies problematic in the absence of solid engineering theories to guide the work; as the collection and storage of accurate and precise experimental data are prohibitive without theoretical guidance furnishing insight into where to focus limited measurement capabilities, etc.The proposed three year research effort aims to arrive at an accurate and useful general engineering theory pertaining to slamming in high speed hull forms of all sizes and configurations. The PI believes that the time is right for such an undertaking, as modern computational approaches and hardware capabilities have advanced to a stage where computational simulation can afford needed insight into the slamming phenomenon. Such insight is required in order that tentative theoretical descriptions might be arrived at to guide a program of strategic experimentation, so that the tentative theories may be refined, extended, and subsequently validated. The latter theoretical validation hinges on the availability of a high fidelity ~computational microscope~ in order that the slamming phenomenon might be initially studied in unprecedented detail; in order that a subsequent theoretical description might be arrived at to guide experimental design, and to serve as the point of departure for subsequent theoretical refinements. Once the tentative theory is in place, strategic experimentation can be carried out in order that refinements can be made, and the resulting theory validated. The ~computational microscope~ to be used in the proposed research comprises the recently developed partitioned fluid-structure (FSI) analysis framework that employs the PI s open source structural dynamics (CSD) code, CU-BEN, the open source computational fluid dynamics (CFD) code, OpenFOAM, and the closed source Python coupler developed at NSWCCD by Kim and Miller. As part of the proposed work, the PI and his Ph.D. student will complete validation of the partitioned FSI simulation capability, using the target of opportunity experimental slamming research work being carried out at the University of Maryland by Professor Jim Duncan s group. The current project encompasses an experimental validation of the ~computational microscope~ order that it may subsequently be brought to bear on the development of a general engineering theory for slamming.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 23, 2019
- Source ID
- N000141912034
Entities
People
- Christopher Earls
Organizations
- Cornell University
- Office of Naval Research
- United States Navy