• The solution to Newton's GEXACT VALUE & FORMULA
  • The pressure at the centre of a massTHE MATHEMATICAL LAW (calculator)
  • The pressure at the centre of a massEARTH'S INTERNAL STRUCTURE (calculator)
  • Proof of the non-exitence of Dark MatterDOES NOT EXIST
  • The atom as Newton and Coulomb describe itNO NEED FOR A UNIFICATION THEORY
The solution to Newton's G1 The theory controlling planetary spin2 Pressure at the centre of the Earth3 Proof of the non-exitence of Dark Matter4 The atom as Newton describes it5
access to the technical calculator
Q & A General 2ᴺᴰ Moment of Area 2ᴺᴰ Moment of Area+ Added Mass & Drag Areas & Volumes Balancing (rotary) Beam Strength Beam Strength+ Bearings (low friction) Bearings (plain) Bending Moments BiMetallic Strip Buoyancy Carbon Steel Catenary Catenary+ Cathodic Protection Centrifugal Force Colebrook & Fanning Column Buckling Combined Stress Co-ordinates Copper Alloys Core Pressure Electrical Current Elliptical Curves Engineering Basics Explosions Fans Fatigue Flange Gaskets Flanges Floors Fluid Forces Fluid Numbers Friction Galvanic Corrosion Gears Hardness Conversion HPHT Flexible Pipe Lift Rigging Logs & Trig Machining Tolerances Metal Properties Mode Shapes Mode 14 Newton's Laws of Motion Ocean Waves Optical Lenses Padeyes Partial Pressures Piling Pipe Flow Pipe Flow+ Pipe Strength Planetary Spin Plastic Stress in Beams Plate Deflection Pressure Vessels Reel Capacity Resolution of Forces Screw Thread Machining Screw Threads Shafts Shock Loads Spring Coefficients Spring Strength Steel Beam Sizes Stress Concentration Table of the Elements Thermal Conductivity Trigonometry UniQon Upheaval Buckling Velocity & Acceleleration Vessel Motions Vessel RAOs Vibration Damping Vortex Shedding Walls, Barriers & Tanks Weight Lifting Welding Wire Rope

Q&A forum: Vessel Motions
(displacements, velocities and accelerations)

All relevant questions concerning this program will be posted here along with our answers for everyone to view.
Please forward your questions to info@calqlata.com or visit our Contact Us page.

Trying to use Vessacc and RAO we found that applying the DVN rules was giving lower results than the harmonic for small waves.

We bought another version through one of my young engineers (Vasilis Papadopoulos) and then we found that there was a problem in the previous editions of Vessacc and RAO which I got.

We check also the waves but we found no problem between the 2 editions.

I am sending you, for your consideration, the slides with the comparison, together with the excel file of the data. The results are for a specific angle μ (angle of wave direction in respect to vessel direction), and a specific angle θ (angle through the wave). For different angles you get bigger or smaller x,y,z components for acceleration.

Your customer has indeed recognised an error in the earlier version (1.0) of Vessac
It is a coding error that was corrected in the later version (1.2)
... this was the only correction made to the calculator
The latest version is correct and the earlier version is not correct.
The issue raised by your customer only applied to the Classical Harmonic calculation option of version 1.0, it did not apply to the DnV Rules for Ships calculation option.

Any customer running version 1.0 of this calculator may contact CalQlata direct for a free copy of version 1.2 in which the above error has been corrected.

...
Having read the technical help, I would like to ask you the following:
Input zᴿᴬ is defined as heave RA in m. In the technical help doc you say that you must enter the amplified response itself, and the amplified response operator (RAO).
Output zᴳ is defined as heave in m @ CoG

I would expect output zᴳ to have the same value with input zᴿᴬ, which is not the case when I run the analysis.

Is it possible to give me some insight?
...
zᴿᴬ is the RA (in metres) at the vessel's centre of gravity
zᴳ is the actual movement of the vessel at the CofG taking acceleration and velocity and phase angles into account

The maximum heave at the vessel's centre of gravity will not necessarily occur at the peak of the wave and accelerations and velocities will cause the vessel to move independently of the water in which it sits.

(No relevant questions have been issued for this program to date)

CalQlata™ Copyright ©2011-2018 CalQlata info@calqlata.com Site Map Terms of website use Our Store