公告

2012-08-05

报告人: | Francis Noblesse, Ph.D., David Taylor Model Basin, USA |

时 间: | 2012-08-14 14:00 |

地 点: | 木兰船建大楼A1008 会议室 |

主 办: | |

联系人: |

报告内容简介：

The classical Neumann-Kelvin (NK) linear potential flow model of 3D flow around a ship hull

steadily advancing in calm water will be reconsidered, and a modified theory --- called

Neumann-Michell (NM) theory --- will be summarized. The main difference between the two

theories is that the line integral around the ship waterline that occurs in the classical NK

boundary-integral flow representation is eliminated in the NM theory. This elimination of the NK

waterline integral is achieved, in two steps, using (i) a consistent linear flow model (the NK theory

in fact corresponds to an inconsistent linear model) and (ii) a mathematical transformation (that

amounts to an integration by parts). Two other notable features of the NM theory are (i) a highly

simplified Green function (which makes it possible to compute the flow around a ship hull in a few

seconds on a PC), and (ii) a practical method for filtering short waves. The NM theory amounts to

a correction of the classical slender-ship approximation proposed by Hogner about 50 years ago.

The NM correction of the Hogner Approximation yields more realistic predictions --- notably of the

ship drag and the wave profiles along the ship hull surface --- in better agreement with experimental

measurements. In particular, the excessive oscillations (humps and hollows) of the wave drag that

occurs in the Hogner slender-ship approximation (and the related Michell thin-ship approximation)

are largely eliminated in the NM theory. This notable improvement requires no significant increase

in computational efforts.

报告人简介：

Dr. Francis Noblesse obtained an American PhD in hydraulics from the U. of Iowa in 1974, and a

French Doctorate in hydrodynamics from the U. of Nantes in 1984. He will soon retire from the

David Taylor Model Basin, where he has performed research in ship hydrodynamics for the past

thirty years. He also held positions at universities in the USA (U. of Iowa, Stanford Univ, MIT) and

in France (U. of Nantes and Poitiers). The results of his research work are reported in about 150

publications. His recent work has considered analytical relations for ship bow waves, analytical

verification of CFD predictions, and a modification -- called Neumann-Michell theory -- of the

classical Neumann-Kelvin theory of ship waves. He was chosen to deliver the Weinblum Memorial

Lecture in 2000.

欢迎大家参加！

联系人：万德成 教授 Email: dcwan@sjtu.edu.cn