Fluid Dynamics News

Computational Fluid Dynamics (CFD) can be used to provide an accurate simulation of the response of complex offshore floating structures under realistic sea states, including extreme weather conditions. (Image: HR Wallingford)

New Tools Optimize the Design of Floating Renewable Energy Devices

, “What our new research shows is that by combining open-source numerical tools, we have the potential to simulate with accuracy the response of complex offshore floating structures to environmental loads in the marine environment.”The toolkit consists of two main components: Computational Fluid Dynamics (CFD) using Proteus open-source software, and Multi-Body Dynamics (MBD) using the Chrono open-source solver.  Both models have been thoroughly validated separately and together.Dr. Aggelos Dimakopoulos, Senior Engineer at HR Wallingford, added, “We have put a special focus on the fully

The William B Morgan Large Cavitation Channel (LCC) is a large variable-pressure closed-loop water tunnel that has been operated by the U.S. Navy in Memphis since 1991. This facility is well designed for a wide variety of hydrodynamic and hydroacoustic tests. Its overall size and capabilities allow test-model Reynolds numbers to approach, or even achieve, those of full-scale air- or water-borne transportation systems. (Photo: U.S. Navy)

Navy Tests Scale Models in Big Facilities

observed and recorded during the runs,” Foster added.The tests can be run in many iterations to validate and improve the computer modeling capability at Carderock.A significant amount of testing is conducted before coming to the LCC. “We can do our computer modeling of the computational fluid dynamics, then build a physical model to test in our tow tank. Then we can test that model, or a larger one, in the LCC. Eventually, our signatures department can conduct acoustic testing at the ARD in Idaho.Using data obtained from testing models in the Carderock facilities, the computer models are improved

(U.S. Coast Guard photo by Stephen Lehmann)

Did Dispersants Help Responders Breathe Easier at Deepwater Horizon?

ocean—data that we needed to confirm that the model adequately simulates what actually occurred.   In the model, we carefully weave together several different dynamic physical and chemical effects that are “coupled” together. These included the changing chemical compositions, fluid dynamics and interlinked movements of oil droplets, gas bubbles and seawater in the deep sea.  To understand what happened, these interdependent problems all have to be solved at the same time. The resulting model is very complex. The equations can be solved with a desktop computer—but only

(Photo: James Fisher Subsea Excavation)

New Water Jet Promises to Boost Soil Cutting Capabilities

global market,” said Graham Murdoch, technical director at JFSE, commenting on this latest M/CFE innovation.   “Discussions with our clients identified this enhancement would offer significant benefits,” Murdoch continued. “We undertook a detailed computational fluid dynamics exercise to fully understand the effects of this setup and the results were impressive. We can now cut soils with shear strengths almost double that which any other M/CFE system can realize.”   The jets are now being fitted to JFSE tools which are stationed at strategic hubs in the

Ed Hill (Photo: NOC)

Voices: NOC Executive Director Ed Hill

you interested in the oceans to begin with? I started off like many oceanographers: in a completely different discipline. I’m an applied mathematician and that’s how I started. I was always interested in the sea since I was brought up by the sea when I was a kid. I became interested in fluid dynamics and then realized the ocean was a great place for that. I’ve been running research institutes for nearly 20 years, first a small institution, and then I had the privilege to be in charge of the U.K.’s National Oceanography Center.    What do you consider to be your greatest

Subsea View of Inverted Helical Grooves on Drill Riser Buoyancy (Image: Trelleborg)

Revolutionizing Deepwater Drilling Riser Buoyancy

cost savings and safer well completions, persists.    As companies move to water depths past 12,000 feet the technology they use has evolved. Extensive engineering design work is now performed using specialized software to produce local and global finite element (FE) and computational fluid dynamics (CFD) analysis to develop optimum designs. The ability to model equipment and system responses to environmental forces helps advance product development and design opportunities to maximize operational efficiency, resulting in cost savings, increased service life and multi-functional designs

Ocean engineers from MIT, the University of Minnesota at Duluth and the Woods Hole Oceanographic Institution have accurately simulated the motion of internal tides along a shelf break called the Middle Atlantic Bight — a region off the coast of the eastern U.S. that stretches from Cape Cod in Massachusetts to Cape Hatteras in North Carolina. (Image: Google Earth)

Scientists Uncover Explanation for Hidden Ocean Swell Interactions

could produce a huge number of complicated interactions and there are lots of theories for different types of interactions. So we started testing different theories.”   Terms of agreement The researchers sought to find mathematical equations that would describe the underlying fluid dynamics that they observed in their simulations. To do this, they started with an existing equation that characterizes the behavior of internal tides but involves an idealized scenario, with limited interactions with other features. The team added new “interaction terms,” or factors, into

Partnership Yields New Helical Buoyancy Technology

Buoyancy design also improves safety in challenging environments by eliminating the need for personnel to work below the drill floor to attach a separate apparatus.   The "helical" design is the result of several years of development by Diamond Offshore utilizing Computational Fluid Dynamics and high Reynolds Number Wind Tunnel testing. Diamond Offshore will work with Trelleborg on further application engineering, data acquisition, testing and development of Helical Buoyancy applications across the offshore drilling market.   "Development of this new technology for riser

Image: BMT

CFD Study Calculates FPSO Current Coefficients

BMT Fluid Mechanics (BMT), a subsidiary of the international design, engineering and risk management consultancy BMT Group Ltd, has recently completed a Computational Fluid Dynamics (CFD) study for an oil major operating offshore Nigeria.   BMT’s scope of work included an assessment of the current loading to which the FPSO hull is subjected to, which has enabled the oil major to ensure its mooring systems are fit for purpose. Johnathan Green, Manager for BMT Fluid Mechanics’ Numerical Modeling Group explained, “CFD is becoming more commonplace in the oil and gas sector with

(Courtesy Land Rover BAR)

The Role of Simulation Software in Yacht Racing

of the America´s Cup and got the attention of several yacht designers who offered me to work in their teams. This was the beginning of my current profession.   Matteo: Being a sailor since I was a kid, I think it was natural for me to study Naval Architecture and being attracted to fluid dynamics. I love studying and understanding how a boat interacts with air and water. CFD allows this, and does it much better than a towing tank or a wind tunnel. You can predict the forces acting on the system and also visualize wave patterns, streamlines and pressure distributions on all the components

HydroComp Names Reps for Japan and China

FsTech. Zhang will be HydroComp’s liason and in charge of all sales and support activity for Japan.   Nanging Tianfu Software Co. Ltd (NJTF) was also founded by Zhang in 2011 and employs more than 30 professionals, many of whom are engineers in finite element analysis, computational fluid dynamics, electronics and design optimization. Many of the staff hold master and PhD degrees. NJTF is also the sole agent of Friendship Systems of Germany, co-authors with HydroComp on CAESES-NavCad development

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