Month: March 2017

How to Solve 8 Tough Ocean Engineering Problems with Dynamic Analysis

Many engineers think of dynamic analysis as being required for analyzing risers and moorings in the offshore industry. But dynamic analysis is used in many other marine sectors for alternative applications.

ProteusDS is DSA’s dynamic analysis software. It is used by ocean engineers and industry professionals to conduct a dynamic analysis of systems that are exposed to extreme wind, current and waves. There are many applications for the software outside of offshore oil & gas – so let’s explore just how diverse the software is…

Aquaculture

These systems include traditional fish farms in both circular and square cage designs along with shellfish aquaculture farms. These systems often contain nets which are connected to moored rigid or semi-rigid structures, such as buoys and floating collars.

As the aquaculture industry continues to grow, the number of traditional sheltered sites is declining, and thus an increasing number of installations are operating in regions that are exposed to high energy ocean swell, current, and wind conditions. The need to understand how to design aquaculture installations is necessary.

To support accurate aquaculture analysis, we have recently added wake-shielding and self-shielding models to ProteusDS, which is essential to avoid any overly conservative estimation in the loads on fish farms for installations.

Debris Impact & Cable Contact

ProteusDS has been recently enhanced to model contact between bodies. This technology could be used to predict the effects of ice or a log impacting a floating platform. Alternatively, lines running through a sheave or a chute can be modeled. This capability is under active development, and users interested in testing it should contact us.

Cable Ferry

ProteusDS is used by naval architecture firms to predict the motion of vessels and marine platforms. Used in conjunction with BEM software like DSA’s ShipMo3D, ProteusDS is used to perform seakeeping and manoeuvring studies. These studies can include moorings, towlines and cables.

ProteusDS was recently used to conduct an in-depth analysis of a cable ferry running between Vancouver Island and Denman Island in Western Canada. The ferry was modeled using a 6 DOF rigid body. The model developed captured key sources of loading, including wave diffraction and wind loading on the superstructure. The ferry travelled across the channel using a simulated traction winch that acted on the drive cable.  The cables were modeled using the finite element cable model that also interacts with the bathymetry of the channel. The ultimate and fatigue loads in the cables were assessed using the model.

Image of a Cable Ferry simulation in ProteusDS

 

 Commercial Fisheries 

The ability to model winches, lines, vessels and nets allow for modeling many types of fishing operations. Through numerical modeling of commercial fishing operations, ProteusDS has been used to cut client’s’ costs by limiting snarls and providing feedback on optimal tow arrangements and winch selections. DSA has also generated informative 3D visualizations of the behaviour of fishing gear in the water and supervised flume tank testing of fishing gear.

Elastic Moorings

Elastic moorings are often used in situations where elongation or compliance is needed, but where a chain mooring is not practical or may harm the environment, or where space is limited. The Seaflex elastic mooring technology relies on a viscoelastic rubber hawser with specially formulated characteristics that is used to manage loads.

The load response of Seaflex depends on the time history of loading.This complex hysteretic phenomenon, while well understood from a conceptual standpoint, can be difficult to represent numerically. Seaflex and DSA worked together to solve this problem and accurately model the response of Seaflex mooring technology using nonlinear axial rigidity parameters. This nonlinear axial rigidity modeling capability is also useful for synthetic rope with nonlinear elongation characteristics – such as Nylon.

Image of an elastic mooring in ProteusDS


Towed Arrays & Towfish

ProteusDS can also be used to simulate towed systems such as towfish or towed arrays. For towfish, the foil model is used to model control surfaces. The control surfaces can be actively controlled to maintain depth or altitude. The tow cable and vessel dynamics can be incorporated to perform layback analysis.

Similarly, the high fidelity cubic finite-element cable model can be used to analyze the loading and profiles of high speed towed arrays for seismic or defence applications.

Launch & Recovery 

Safely deploying and recovering equipment (spools, jumpers, AUVs, ROVs, small craft) from vessels in various sea conditions is a potentially high risk operation. Predicting the limits of safe launch and recovery operations in terms of human factors, loading and motions can enable operators to make good decisions in the field and prevent errors.

ProteusDS contains a mechanism modeling and control infrastructure that model A-frames, cranes, and other handling equipment. Offloading, lowering, and many other operations can be simulated. An important benefit of this type of analysis is that visualization of these simulations helps managers, analysts, and others better communicate with each other about how complicated operations will take place.

Image of a launch and recovery simulation in ProteusDS of a recovery boat from a frigate

Tidal Device Installation

In many ocean sectors, sea trials or operator experience largely guide routine marine operations. However, in tidal energy, the strong directional currents and narrow deployment windows make it difficult to perform sea trials safely and cost-effectively, and there is often less operator experience. ProteusDS has the ability to perform fully coupled analysis of floating service vessels installing structures such as tidal turbines, floating platforms, or laying cable.

Modeling the waves and currents in tidal passages is important for these assessments.  ProteusDS contains a spatially and time-varying current modeling capability that enables accurate representation of large-scale eddies and turbulence which will impact towing operations.

Image in engineering mode of the Cape Sharp Tidal platform with tug configuration in ProteusDS dynamic analysis software.

 

 

Designing for the ocean environment is a constant challenge. Dynamic analysis with ProteusDS allows for rapid innovation and optimization while reducing risk.

To learn more about DSA’s services, or licensing the ProteusDS software please feel free to:

ProteusDS v2.34

Release Date: March 23th, 2017 (v2.34)

ProteusDS v2.34 Release Announcement

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

ProteusDS v2.34 is now available

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

Western Economic Diversification

Dynamic Systems Analysis recently took part in an initiative with Marine Renewables Canada to further emphasize the opportunity that marine renewables can bring to Canada.  DSA submitted a  letter of support to the Western Diversification Program to demonstrate the opportunities and benefits industry development is creating for local businesses, communities, and organizations across Canada.

The purpose of this outreach initiative is to broaden the current dialogue around marine renewable energy companies to ensure they have opportunities to provide expertise and solutions to the growing marine renewable energy market.


To whom it may concern:

RE: Western Diversification Program Call for Proposals – Marine Renewables Canada’s Supplier Engagement and Development Initiative

Dynamic Systems Analysis Ltd.(DSA) strongly supports Marine Renewables Canada’s proposal for its Supplier Engagement and Development Initiative which is aimed at supporting Western Canadian companies (namely SMEs) in participating and benefiting from the emerging marine renewable energy sector. As a new cleantech sector, marine renewable energy development requires a range of enabling technologies, expertise, and innovation that is currently present in Western Canada.

Marine Renewables Canada’s past work with its membership in British Columbia, Manitoba, and other areas of Canada has been successful in helping Canadian companies gain new business development opportunities and carving out a leadership role for Canada in this new cleantech sector. We are particularly pleased to see Marine Renewables Canada leveraging past work and current funding from other sources to ensure that Western Canadian companies and organisations can play a role in local, national, and international marine renewable energy advancement.

DSA is an ocean engineering consultancy and software company. We provide progressive and accessible dynamic analysis software and expertise which makes it possible for ocean engineers, naval architects, oceanographers – or anybody with business in the water – to assess the motions and loads on vessels, structures, lines, and technologies in marine environments.

Over the years DSA has thrived providing engineering services as part of a growing supply chain to companies developing renewable energy technologies destined for areas like the Bay of Fundy, across Canada and around the world.

DSA has invested and will continue to invest, in developing our dynamic analysis software, ProteusDS, which will continue to contribute to advancing marine renewable energy. However, because this is an emerging technology there is a need for continued support to assist companies/SMEs in participating in the sector and developing solutions that have global applications.

We fully support Marine Renewables Canada’s proposal and look forward to the work the association will do to catalyze and facilitate development of a national marine renewable energy industry in which Western Canadian companies play an important role.