Tag: aquaculture

ProteusDS v2.36 is now available

Posted on July 4, 2017
Lauren Dunn

DSA is very pleased to announce the release of ProteusDS v2.36. The software is ready to go and active subscribers can use their login credentials to download the latest version from our website. We’ve highlighted some of the key new features below.

Support for visualization-only models

A good computational model is very different than a 3D model used for purely visualization purposes. Because of this, we have added the ability to handle models that are to be used for visualization purposes only. Now, in the ProteusDS Simulation Toolbox, you can add a $VisualizationModel property to a RigidBody. The model specified through this property is not used for computations. We have added functionality in both PostPDS and ProteusDS Simulation Toolbox to toggle visualization or computational models on or off.

Image of Blended copmutational vs visualization labels

Comparing computational and visualization display modes in PostPDS

Bathymetry analysis

We have released a set of powerful bathymetry analysis features in PostPDS that allow users to assess seabed slope and depth. To access these features, simply right-click on the Seabed item in the Categories tree in the UI, and select the appropriate Bathymetry Plotting option. The depth and slope plots now have legends that make it easy to interpret seabed data. The exclusion zone plot allows you to find safe regions to place equipment or position anchors.

PostPDS showing the slopes in a bathymetry file using the bathymetry plotting options

Modeling ropes that are sewn into nets

For our aquaculture and net-modeling users, we have added support for modeling rib-lines or “structural lines” that are frequently sewn into nets to add strength and shape. This is done within the Net DObject itself and not using additional Cable DObjects. This dramatically reduces the numbers of DObjects and connections required to simulate a net pen with rib lines leading to faster simulations. To apply a rib-line to a net, use the $ExtCableLongitudinal or $ExtCableTransverse property in the Net input file.

We have also added an option to connect the end of a line to any point on a net. You do not have to connect a line directly to a node! This is much easier for creating supporting lines in net pens. To create this connection specify the Net as the master and the Cable as the follower, and use the Point connection type.

Image of structural lines that are swen into net panels

Visualization of structural lines (indicated in yellow) that are sewn into net panels.This feature reduced net analysis complexity significantly.

So, that’s ProteusDS 2.36 – we hope you enjoy it and find the new features useful.

v2.36 Changelog

Additions:

Added time history plot functionality for RigidBody DObject in PostPDS
Added legends for bathymetry plots in PostPDS
Added support for computational and visualization models in ProteusDS solver, PST, and PostPDS
Added height above seabed probe to RigidBody to check for clearance
Added inclination angle and tension output for ExtMass and ExtMassCylinder attachments
Added ability to connect the end of a cable to anywhere on a net panel
Added ExtCable functionality to Net DObject to allow for modeling of ropes which are sewn into nets to provide strength and shape

Changes:

Enhanced ‘Duplicate Selected DObject(s)’ functionality to allow for optional duplication of connections

Resolved issues:

Addressed overlapping water rendering
Improved full-screen support with ability to toggle the display device that the full-screen window appears on by pressing ‘F1’
Addressed mooring line naming issue with taut leg mooring generator

View our 2015 changelog here

ProteusDS v2.34 is now available

Posted on March 23, 2017
Lauren Dunn

v2.34 is now available

It’s been an exciting and busy start to 2017 here at DSA and it’s been several months since our last release of ProteusDS (v2.29) – so we are very pleased to announce the release of ProteusDS v2.34.

The software is ready to go and login credentials for active subscribers will allow you to access ProteusDS v2.34 from our website.

Version 2.34 introduces new functionality, including:

Net modeling enhancements

The latest version of ProteusDS contains fixes and enhancements for net modelers. Improvements have been made to increase the accuracy of predicted hydrodynamic forces on nets, and mooring components in the wakes of nets. The pre-existing wake-shielding model, which accounts for fluid velocity reduction through nets, has been updated and is considered essential for not over-estimating forces on successive net pens in simulations. This builds on the self-shielding model that was added in the previous release to account for local hydrodynamic shielding between adjacent net twines at low angles of incidence

Secondly, automatic adjustment of net twine drag coefficient with Reynolds number has been added as default to nets, and has been proven to accurately estimate hydrodynamic forces on nets over wide ranges of fluid velocity. DSA has produced a validation document which outlines the net model developments for estimating hydrodynamic loading and comparisons made to experimental tank tests of nets and full-scale fish farms. It is critical that net users add to their existing net model input models the $FluidCoefficientReData property.

Enhancements have also been made to the net arc space calculations in ProteusDS, which is used to position external masses on nets. Performance improvements were made by switching from a bi-quintic to a linear-cubic interpolation scheme.

The image shows a side view of three successive square aquaculture pens, with current flowing right to left. The leading cage experiences the largest hydrodynamic forcing and netting deformation. Current velocity is then reduced with the wake shielding model as the flow traverses through multiple nets, as seen in the middle and trailing cages.

Lastly, improvements have been made to previsualization of nets in the ProteusDS Simulation Toolbox. Users can now distinguish which net edge is which according to its colour.

Users can now distinguish which net edge is which according to its colour.

Cable model damping optimization

The finite-element cable model is one of the core models in ProteusDS. Users will now have the ability to automatically estimate a reasonable axial damping coefficient in cables based on a damping ratio, axial stiffness and element lengths. Testing has shown that this typically results in major simulation speed-ups.

Simulation execution time can be greatly increased by utilizing automatic cable damping, as each instance of a cable segment defined in a cable has a particular calculated axial damping coefficient based on the average element stiffness, average element length, and cable node mass covered by the cable segment.

Environmental condition transitions

The latest version of the ProteusDS contains a major new feature that allows control over the application current, wind and waves in a simulation. We’ve added the ability to independently control when the current, wind, and wave conditions will start in any given simulation and the length of time that those conditions will be ramped to their set state.

Previously the singular $TRamp property was used to control ramping of all environmental conditions. Users could not, for instance, have a steady state current with wind and then have waves start at some point later on in a simulation.

This feature is very useful when a user wants to determine an initial steady state configuration (positions and loads) for a model (e.g. a mooring system, a fish farm, a moored buoy) – then after the steady state is reached, introduce unsteady wave loads. Previously this level of analysis was only achievable after running separate simulations.

So, that’s ProteusDS 2.34 – we hope you enjoy it and find good use for all the new features.

Complete list of additions, changes and resolved issues.

Additions:

ProteusDS Simulation Toolbox pre-visualizer now displays name of any currently selected DObject(s)
Added Net edge and ribline colouring to pre-visualizer
Added automated calculation of axial damping for Cables/Scables using $AxialDampingMode property
Added environmental timing/ramping options to the Environment input file which allows users to set the start time and ramp duration independently for wind, waves and currents.
Improved 2.5D spatially varying current loading
Added Reynolds number dependent drag as default to net panel feature
Added defaults for variation of drag with Re (for cylinders)
Improved drag loading and wake/shielding model for nets
Improvements to simulation destabilization detection

Resolved issues:

Addressed a number of rendering issues in pre-visualizer
Improved performance of pre-visualizer rendering
Resolved out-of-bounds current sampling
Renamed “Transform” to “Translate / Rotate” in ProteusDS Simulation Toolbox

View our 2015 change log here

Aquaculture 2016

Posted on March 7, 2016
Lauren Dunn

Dynamic Systems Analysis sent engineer-in-training, Adam Turner, to Aquaculture 2016 in lively Las Vegas, Nevada.

The triennial conference, presented by the World Aquaculture Society, is the largest aquaculture conference in the world – with nearly 4000 attendees from over 90 countries worldwide. During the four day conference hundreds of technical presentations showcased the many aspects of research being done in the field of aquaculture, such as the biological aspects of aquaculture development, engineering, statistics and economics.

Adam had the opportunity to present his master’s research currently featured in the December 2015 World Aquculture Magazine, in the Integrated Mulit-Trophic Aquaculture session. Adam’s thesis work focused on the hydrodynamic wake properties of scale model fish cages and fish cage arrays, to gain a better understanding of wake velocity, wake topology, wake turbulence and wake recovery. The results of his work are being used to better understand how to place extractive species in aquaculture farms for optimized nutrient extraction.

In addition to the numerous technical presentations, Aquaculture 2016 hosted a large trade show, where Adam had the opportunity to network with other industry professionals and see first hand the latest products and services in the aquaculture industry.

Aquaculture 2016 was located in the beautiful Paris Hotel, a French-themed casino hotel with a half-size Eiffel Tower, on the bustling Las Vegas Strip. Overall the conference was a huge success. We’d like to thank the World Aquaculture Society and the city of Las Vegas for their hospitality!

For more information on future DSA conference attendance please click here

About the World Aquaculture Society

The World Aquaculture Society was founded in 1969 as the World Mariculture Society. Since it’s beginning the membership in WAS has grown to more than 3,000 members in about 100 countries representing the global aquaculture community. Through its diverse membership and international networks, the WAS provides leadership for enhanced international communications, collaboration and information exchange. The World Aquaculture Society is a dynamic organization capable of responding to change and is recognized for its professional credibility in aquaculture science, technology and education.

DSA Employee Featured in World Aquaculture Magazine

Posted on December 17, 2015
Lauren Dunn

Bridging the Gap

Environmentally Friendly Aquaculture Design

Did you know that aquaculture is responsible for the production of roughly 50% of the world’s seafood? In Canada aquaculture accounts for 14% of the total Canadian fisheries production and 33% of its value. The aquaculture industry plays a vital role in all Canadian provinces and territories, employing nearly 10,000 people primarily in small communities.

Aquaculture has been around for thousands of years but has only been recognized as an industry in western society for four decades. During this time period, poor government regulation, environmental impacts and lack of industry promotion has had a negative impact on the image of the aquaculture industry.

In steps Adam Turner, a recent graduate of the Master of Science in Mechanical Engineering program at the University of New Brunswick, who is currently a Mechanical Engineer in Training at Dynamic Systems Analysis (DSA). Adam’s master’s thesis focused on the hydrodynamic wake properties of scale model fish cages and fish cage arrays, to gain a better understanding of wake velocity, wake topology, wake turbulence and wake recovery. The results of his work are being used to better understand how to place extractive species in aquaculture farms for optimized nutrient extraction.

By focusing his studies on how water moves through fish cages and cage arrays, Adam is helping the aquaculture industry understand how current flow will impact nutrient and waste flow, and how that impacts surrounding habitats. Adam also draws attention to the vital role extractive species (mussels, sea cucumbers, kelp, etc.) play in and around aquaculture farms, as they have a natural ability to recycle nutrients or waste, making them a living filter.

Green dye can be seen moving with the current flow.

Adam’s scale model testing research (currently featured in the December Issue of the World Aquaculture Magazine), suggests that the placement of extractive species, and current flow through cages should be an important consideration for any aquaculture farm as it will help to reduce the environmental impact these farms have on the surrounding marine environment.

From theory to practice, Turner is focusing his attention on aquaculture engineering projects at Dynamic Systems Analysis using their ProteusDS software. The software plays a vital role in allowing Adam to easily and effectively conduct mooring, motion and anchoring analyses, with use of ProteusDS’ built in hydrodynamic cable and net models. The data gained from these assessments will play a vital role in helping producers and site managers in the protection and maintenance of their aquaculture farms.

Heading to Aquaculture 2016 in Las Vegas? Check out Adam’s session IMTA/Aquaculture on Wednesday, February 24^th at 10:30am.