2.20 Release

Important notices

Regarding lift and impermeable membranes

In 2.19 we changed the definition of lift. We encourage users who work with impermeable membranes to review TR-FOU-2328-5.

NB: The default value for the lift coefficient has changed from 2.4 to 1.0.

Introduction of improved current reduction behind nets

We have introduce a new formulation in addition to the established Lølands forumla, the Energy method, for calculating current reduction behind nets. More information can be found in TR-FOU-2500-1_Rev2.

Reduction of drag coefficient for nets

The drag coefficient to nets in AquaSim has been updated. The coefficient for a net will be approximately 10% lower than previously. Note that when using Løland to account for current reduction, the original Løland drag coefficient is used as basis whereas for the energy method the actually derived drag coefficient is used. Further information is available in TR-FOU-100004-6.

Improved membrane properties

Membranes are complex and span multiple different types of materials, causing these dialogs to become complex. We’ve reviewed naming and grouping of properties as well as added additional properties. Please see TR-FOU-100004-7_Rev1 for more information and review of the parameter grouping, and Chapter 2.14.5 in the AquaEdit manual.

Important notice to system administrators

The AquaSim package no longers requires write permissions to %PROGRAMFILES%. All logs and additional data is store either in the users Doucments folder or %APPDATA%\AquaSim.

Note that activating AquaSim and downloading solvers is considered part of the installation locally to the computer, and requires Administrative privileges and writes to %PROGRAMFILES%\Aquastructures\AquaSim\ (or the location AquaSim has been installed to).

Full changelog

AquaSim:

  • #1806: Factors for how much added mass and hydrodynamic damping to introduced has been split such that it is now possible to apply a different factor for added mass in the vertical direction than in the horizontal direction.

    This means that 3 more parameters are introduced to the impermeable net section:

    • How much inner mass to account for vertically
    • How much added (external) mass to account for vertically.
    • How much hydrodynamic damping to account for vertically.

    Note that this means old input files may lead to different results in the updated solver.

  • #1749: Calculation of how drag and lift to impermeable net are calculated has been updated. The formulation has been altered to cross flow in order to be more versatile. Now drag coefficients are givens separately for the upstream and downstream part of an impermeable net cage. This is documented in TR-FOU-2328-5.

  • #1838: Updates on contact elements to what is written to file. For line to line elements edge case close to nodes have been included.

  • #1932: There was a mismatch in writeout of elongation for nonlinear net elements. This has been adjusted.

  • #1803: An option to apply the “Energy” method as alternative to the Løland formula to account for current reduction behind nets has been introduced. This is further described in TR-FOU-2500-1_Rev2.

  • #1823: Recent years more empirical data to drag on nets have been available. Also the fact that solidity shall be measured by photographic technique has been settled. Based on this as well as more analytical considerations, the drag coefficient to nets in AquaSim has been updated. The coefficient for a net will be approximately 10% lower than previously. Note that the using Løland to account for current reduction, the original Løland drag coefficient is used as basis whereas for the energy method, the actually derived drag coefficient is used. Report TR-FOU-100004-6 covers this.

AquaEdit:

  • Default lift coefficient on membranes has been reduced from 2.4 to 1.0 (#1823)
  • Added mass split into vertical and horizontal components
  • Current reduction can now be changed between Løland and Energy method (#1803)
  • Rearranged membrane properties (#1749)
    • Improved grouping, naming, and tooltips
  • Default value for growth coefficient changed from 1.5 to 1.3 ref new standards (#1926)
  • Improved orthographic view
  • Normal axis on membrane X is now scaled based on size of the element for cleaner visuals
  • The coloured node indicators on Membrane X elements are now only visible when 1 element is selected for cleaner visuals
  • New verification rules:
    • Lift on membranes over 2.3 causes warning
    • Using features that are new in 2.19 will cause errors when using an older solver (2.18.1 and older)
  • Fixed some properties not being copied when duplicating load case tabs
  • AVZ files are generated automatically when using buckling/eigen period analysis

AquaView:

  • Improved orthographic view
  • Fixed colour rendering of AquaCross cross sections
  • A warning is now shown when opening AVZ files that have been split
  • Holding CTRL and using the arrow keys now nudges the view in the direction of the arrow key pressed
  • “Set camera” is improved to work with user specified coordinates (an axis “wobble” can still happen)
  • “Sparse” data can now be loaded from AVZ files (#1927)

PostProcessor

  • Introduced the option to generate max-out files from inside the user interface of PostProcessor

Other:

  • ppreduce now officially supports element positions using Position.X_[m], Position.Y_[m], and Position.Z_[m]