marine hydrodynamics -- a memoir - ntnu
TRANSCRIPT
Marine Hydrodynamics -- a memoir
70 years anniversary seminar and celebration
for
Professor Odd M. Faltinsen and Professor Torgeir Moan
NTNU, Trondheim
19-20 May 2014
by J. N. Newman
NTNU, MIT, WAMIT Inc
Outline
• Early days of my own career (1955-1960)
• Interactions with Torgeir and Odd (1969 … )
• Computations of 3D wave effects (1980’s … )
• Closing thoughts
1955-1960 Mentors and Heroes
Martin Abkowitz, MIT
Fritz Ursell, Cambridge
Georg Weinblum, Hamburg
M. D. Haskind, Odessa
T. H. Havelock, Newcastle
John Wehausen, Berkeley
Reinier Timman, Delft
Photo: Norwegian Petroleum Museum
“The Alexander L. Kielland Accident”, by Torgeir Moan
First Wallace Lecture, MIT, June 1981
Evolution of radiation/diffraction codes
• Submerged bodies: Halkyard/Milgram (1971)
• Floating bodies: Garrison, Hogben/Standing, v.Oertmerssen, Faltinsen/Michelsen
• Alternative methods (FEM): Bai, EatockTaylor/Wu, Yue/Chen/Mei/Aranha
• Special challenge in 1980’s: TLPs
ISSC TLP comparisons from `Variability of hydrodynamic load predictions for a
tension leg platform’, Eatock Taylor and Jefferies (1986)
`My’ Computers
Year1950 1960 1970 1980 1990 2000 2010
10-2
10-1
100
101
102
103
104
105
CPU, MHz
RAM, Mbytes
IBM 704
IBM 7090
IBM PC
PC/AT
PC(8 core)
Cray
PC(1 core)
MAINFRAMES
Personal Computers(PC)
`My’ Computers
Year1950 1960 1970 1980 1990 2000 2010
10-2
10-1
100
101
102
103
104
105
CPU, MHz
RAM, Mbytes
IBM 704
IBM 7090
IBM PC
PC/AT
PC(8 core)
Cray
PC(1 core)
MAINFRAMES
Personal Computers(PC)
`Cloaking’ a circular cylinder in deep water Surrounding structures optimized to minimize scattered energy at
Kd=1 (wavelength = 2𝜋 × draft)
Array of 64 circular cylinders
E/E0 = 2 x 10-8
Ring with varying radius and depth
E/E0 = 5 x 10-9
y
x
y
x
Comparison of drift forces black: no rings red: with rings
Period (sec)
DF
x
6 8 10 12
2
4
6
8
10
12
14
semi
semi + rings
More challenging problems
• Forward velocity (ships in waves)
• Nonlinear (steep / breaking waves)
• Viscous effects including separation
Extensive software is now available `off the shelf’
Great assets for offshore engineers and
naval architects,
but also a challenge to use intelligently
Good teaching and good students are vital!