14. RECENT MICHLET REVISIONS
Version 8.07: Released 6 November 2005
- Hull offsets are now also automatically saved in a format that
can be read by Martijn van Engeland's program FREE!Ship. The offsets
can be found in the files named fsoff1.txt,...,fsoff5.txt.
- Included batch file michlet.bat to run Michlet, and godzilla.bat
to run Michlet in GODZILLA mode.
Version 8.06: Released 18 October 2005
- Mostly minor modifications in preparation for better communication with
Martijn van Engeland's program FREE!Ship.
- Maximum total ship displacement increased to 999999.9 tonnes.
- Maximum speed increased to 52.0 m/sec (about 100 knots).
- Updated skin friction line based on Grigson's Method. Changes
are fairly minor and will be only be apparent at low Reynolds numbers,
typically below about 2 million.
- Updated method of calculating Michell P,Q functions in infinite
depth water. These functions are now exact for hulls with piece-wise
quadratic waterlines and piecewise quadratic sections, for example,
parabolic struts and Wigley hulls.
- Dimensions of Wigley hulls in examples changed slightly to be closer
to exact values. The correction was very small, but necessary in order to
verify that exact Michell P,Q functions were being calculated by Michlet.
- Bottom pressure signature calculations uncrippled but still need
validation. Scaling of pressure still needs checking.
- Uncrippled GODZILLA ship ID objective function and included
inverse ship example. At this stage, only two wave cuts can be used.
- Included option to allow or disallow hull boundary layer
displacement thickness effects on wave patterns and wave resistance.
Using a negative value for Ntheta turns off boundary layer effects
(which are negligible for all but small hulls) and slightly reduces
execution times.
Version 8.05: Released 10 January 2004
- Implemented an extended version of Grigson's algorithm method for
estimation of skin friction.
- New examples: LA class submarine, FFG8 frigate, and lightweight men's
rowing shell.
Version 8.04: Released 1 May 2003
- Michlet now runs in a window rather than full-screen under DirectX.
- Graph axis labels have been tidied up.
- Pressure signature module implemented.
- Michlet now has four variants: Demo, Basic, Pro, and ProSig.
Version 8.03: Released 23 February 2003
- Spline offset input method made more robust. In
previous versions, all input had to start in the first column
with no leading spaces. Michlet is now a little more tolerant of
'untidy' input.
- New boundary layer displacement thickness calculation. Some
calculations for small model hulls will be different to earlier versions,
however for full-size vessels the change should be insignificant.
- Fixed some errors in output files when submerged hull
volume is equal to zero.
- Transom stern calculation method has been modified. Results at very
low Froude numbers are now a little better. Comparisons with experimental
results for small model hulls at low speeds should always be treated
with caution as viscous effects are dominant.
- Increased maximum Ntheta to 4096. Wave elevation
calculations in finite-depth near the critical depth-based Froude
should be a little more accurate.
- Added DDG51 destroyer hull example.
- Included Excel spreadsheet containing some comparisons with
experimental results.
Version 8.02: Released 18 December 2002
- Demo version and special release.
Version 8.01: Released 5 May 2002
- New input format. Old input files will need modification.
Comments can now be added almost anywhere in the input file, as
long as they are preceded with # in the first column. Files can
be stripped of comments completely, making it easier to work with
gnuplot and freely-available scripting tools.
- New offset input method allows unequally-spaced stations
and waterlines.
- Several new output files readable by Excel and/or gnuplot.
- New objective function: Required power = total drag * speed,
for a range of (weighted) speeds.
- Added intact stability constraints: KG, BM.
- Added geometric constraints: Cm, Cwp, L/B, L/T, B/T.
- Added constraints on transom sterns: the transom area, beam and
draft can now be constrained during the optimisation.
- Increased maximum number of fitness evaluations to 1000000.
- Implemented better eddy viscosity method for attenuation of
far-field waves.
- Fixed slight inaccuracy in wave resistance calculations for
very large vessels at high speeds.
Versions 7.02-7.30: 2001
Version 7.01: Released 4 October 2001
- Graphics version now works under more versions of Windows.
- Included new method to specify hull offsets. Unequally-spaced
stations and waterlines can now be used.
Version 6.00-6.06b: Released 13 March 1999 to 17 March 2001
Back to Index.