Further Insight into the Hydrodynamic Phenomena Influencing Motions, Dynamics Loads and Performance of High Speed Craft in a Seaway
Abstract
ABSTRACT: The flow field around a High-Speed Craft (HSC) is complicated; the hull acts as a lifting surfacecausing unique flow phenomena and loads. The main hydrodynamic engineering challenges forHSC are to increase the performance, decrease accelerations, and decrease damaging slammingforces. These challenges are commonly addressed through either experimental methods (towingtank testing) or empirical/analytical and numerical models. Empirical methods have limitations intheir accuracy, and numerical models for HSC are not yet as accurate as their counterparts fordisplacement hulls. The reason is that many of the physical phenomena related to planing craft,are not yet fully understood.In this project, model scale towing tank testing will be used to shed light on some key flowmechanisms underlying the hydrodynamics associated with High Speed Craft advancing in calmwater and rough seas. The target phenomena have been chosen based on identified knowledgegaps, the closing of which is required to further develop numerical models to a higher degree ofapplicability to HSC. This project will investigate how flow separation effects calm waterresistance, running position, added resistance and acceleration in waves but also how slammingand global bending moment relates to hull rigidity.We have previously found that forcing separation to happen using spray deflectors/rails canimprove calm water performance but that the location and shape of the spray deflectors isparamount. For optimal detachment, correct determination of the stagnation line is required. Thisis, however, something current state of the art numerical and semi-empirical methods struggle topredict. Accelerations and slamming forces are important measurements of vessel performance inwaves and accurate predictions of head seas performance will aid in reducing structural weight.Slamming loads are difficult to capture due to their transient behavior; to understand how theyaffect the hull structure, a segmented backbone beam hull will be tested to quantify global bendingmoment and local slamming pressure. Comparing the results to a rigid hull fitted with pressuresensors will give insights into the role hull rigidity plays for performance of HSC in rough seas.All datasets will be readily available to the scientific and boat building communities for rapiddissemination of the gained knowledge.In conclusion, the project will contribute to both better design of HSC and a better understandingof the fundamental flow physics around such craft, while also creating validation data sets tofurther enhance the development of hydrodynamics and fluid-structure interaction models.Ultimately, this project will provide the Navy, numerous private sector stakeholders, and theresearch community with an improved understanding of factors that affect performance, safety,seaworthiness, and structural integrity of HSC.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 08, 2020
- Source ID
- N000142012490
Entities
People
- Mirjam Furth
Organizations
- Office of Naval Research
- Stevens Institute of Technology
- United States Navy