1 / 18

Overview

Incorporation of Steady Flow Effects in Linear Three-dimensional Seakeeping Predictions for High Speed Hulls T.M. Ahmed 1 , D.A. Hudson 1 and P. Temarel 1 1 School of Engineering Sciences, Ship Science, University of Southampton, Southampton, UK. Overview. Introduction Mathematical model

caia
Download Presentation

Overview

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Incorporation of Steady Flow Effects in Linear Three-dimensional Seakeeping Predictions for High Speed Hulls T.M. Ahmed1, D.A. Hudson1 and P. Temarel1 1School of Engineering Sciences, Ship Science, University of Southampton, Southampton, UK.

  2. Overview • Introduction • Mathematical model • Hull forms • Hydrodynamic coefficients • Responses • Conclusions • Future Work

  3. Motivation • Detailed validation studies • Green’s function methods • Develop model to improve predictions • Steady-state flow in unsteady body boundary condition • Cannot include in free-surface condition

  4. Unsteady velocity potential in regular waves Mathematical Model (1) • Assume potential flow • Inviscid, homogenous, irrotational fluid motion • Steady flow velocity vector

  5. Need 2nd derivatives of steady flow Body Boundary Condition

  6. Mathematical Model (3) • Hydrodynamic forces

  7. Manipulate 1st derivatives Analytical Newman (1987) Mathematical Model (3) • Use Kelvin wave-making source for steady flow • Numerically efficient formulation of Baar and Price (1988) • Accuracy of 2nd derivatives important • Adopt analytical/numerical method

  8. Series 60 (1) • Series 60 (Cb=0.7) for initial verification • Pulsating source method applied 510 panels

  9. Series 60 (2) – Fn=0.2

  10. Series 60 (3) – Fn=0.2

  11. Series 60 (4) – Fn=0.2 Pitch RAO Heave RAO

  12. High Speed Monohull (1) • Based on NPL hull form - • Pulsating source method applied • Transom stern omitted 320 panels

  13. NPL Monohull (2) – Fn=0.53

  14. NPL Monohulll (3) – Fn=0.53

  15. NPL Monohull (4) – Fn=0.53 Pitch RAO Heave RAO

  16. Summary • Included steady flow in seakeeping analysis • Kelvin wave-making source for steady flow • Accurate and efficient method for 2nd derivatives • Pulsating source for unsteady analysis • Series 60 and NPL hullforms • Range of forward speeds

  17. Conclusions • Influence of steady flow small • Pitch actions most affected • Improvement in hydrodynamic coefficients • Little change in responses

  18. Future Work • Refine hull idealisations adopted • Investigate for translating pulsating source Green’s function for unsteady flow • Use improved model of transom stern flow for high speed craft • Apply to multi-vessels

More Related