|Evaluation of Prediction Methods for Ship Performance in Heavy Weather
|Applied Vehicle Technology|
heavy weather, propulsion, Ship performance, stability
Physics-based simulation capability for prediction of maneuvering and stability in waves and wind is of timely importance both for surface combatant and transport ships in normal and extreme operations. Issues for naval ships include operability requirements under all sea states, radical/violent maneuvers, frequent course changes, replenishment at sea, and stealth. Issues for transport ships include IMO Guidelines for EEDI, EEOI and Minimum Propulsion Power requirements. Issues for both include operations in deep and shallow water, intact and damaged stability and energy efficient hull forms.
AVT-216 Evaluation of Predictive Methods for Maneuvering and Control addressed issues for normal operations by benchmarking of prediction capability of ship performance in realistic operational conditions at sea and providing guidance for design analysis, including maneuvering in waves, shallow-water operations, and ship-ship interaction. Building on this progress an AVT follow-on activity is proposed for extension for issues of extreme operations by evaluation of prediction methods for ship performance in heavy weather, including issues of propulsion performance and shallow water.
Outcomes of proposed RTG will enable improved simulation capabilities for prediction of maneuvering for surface combatants in extreme operations thereby providing innovative design opportunities to meet challenges of 21st century naval vehicle operational and standardized regulations requirements. The goal is to provide validated tools to improve capabilities for design and assessment of naval vehicles with increased performance. The proposed RTG is of relevance to 2015 NATO S&T Priorities: Platforms & Materials target of emphasis P&M-1.
The scope of the proposed activity is an assessment of prediction methods for ship performance in heavy weather, including issues of propulsion performance and shallow water. Available and required towing tank and wave basin experiments will be identified for benchmark validation test cases. Experimental conditions will focus on extreme motions/maneuvers, propulsive performance and shallow water. Validation data will include both global (6DOF trajectories, propulsion performance, appendage/rudder/control surface forces and moments) and local (wave elevations and flow field) variables. Simulation codes will cover system based, potential flow and CFD. Simulations will guide the experiments and once validated will fill in sparse data, especially for propulsor-hull interactions. Verification and validation procedures will take into consideration both the comparison error E=D-S (where D and S are the experimental and simulation values, respectively) and validation uncertainty, i.e., root sum square of numerical and experimental uncertainties. Recommendations will be provided as to best practices for current simulation methods as well as directions for future research. Synergy and shared experience will be documented in the final report.
Ship performance, heavy weather, stability, propulsion