4 - Memorial University of Newfoundland DAI

then manipulated by the computer roftwnrc to create WB nelaiemd wave
spectrum.
4. Any disnepmcies between the desired wsveapeetrum and tho nd~icvnl
wave spectrum was corrected via an iterali~ pm-8. Va~iiltioo. be tween the two were determined by the cornputor, aurl additional clrivo
signals were created until the differences betwccn lhe desired mal tho
achieved were within acceptable limils.
5. The corrected time history drive signal was spplicd lo lhc wnvc bcmnl
to create inegular waves lor model testing. Collect~~I dnln worn linnlly
manipulated by the system application software lo crcnlc qrretrrl dru-
rity information.
Approximately four houn were required io complctc lhc wnvc ni!n~ilntiou
pracns for each spectrum. (All computations for lhe above alcps were .w-
complished with a special purpasc pmgram (SPECGEN) devclopnl hy Mr.
Lloyd Little, project engineer at tho wave lank lacility.)
5.2.4 Wave Structure Interaction
As a. result of the frequency resolution desirod, and tho nbcmory li#nitntios
of the dsla aequiaition computer st the wave tank facility, tho duration fur
the wave test wae set at thm minutes. Therefore, to wlloct sufnciaul dala
to allow transfer function analyses, ten scparalc runs, for each lent, wcrc
carried out. (A set of tcn runs lasted appmiimately eight hnam.) Thin wn*
aemmpliahed by running a test for three minula (while urllecli~~gdntn), then
stopping the let and allowing tho water in the tank to actllc. Thc water
was considered settled, when the wave pmhc readings showed a pnrtictnlar