At any marine conference or workshop, you will hear many topics being debated: validation and accuracy of CFD predictions, best practices in simulation, the latest industry regulations affecting ship design and many more. One topic that always gets engineers talking and arguing is whether to run your CFD simulations at model scale or full ship scale. There are benefits and drawbacks to both approaches.

Running at model scale means the result can be easily validated by comparison with towing tank data before running new analyses. The model scale results can then be transformed to full-scale data using standard semi-empirical scaling up procedures. However, this approach can introduce uncertainties as the scaling methods may not be suitable for new or unusual geometries or running conditions. This is one of the reasons why ship designers are reluctant to change anything in their designs for which they have collected operational data and know the performance. Running CFD simulation at full-scale may require a higher grid resolution to accurately capture aft end flow especially when appendages are present, but removes the possible errors from the semi-empirical scaling methods.

In the early hours of Saturday May 6, at the Monza motor racing circuit in Italy, Eliud Kipchoge ran 26.2 miles in 2 hours and 25 seconds, beating the existing marathon world record by 2 minutes and 32 seconds. The run was the culmination of Nike’s “Breaking 2” project, a two year program aimed at demonstrating that it is physically possible for a human to run a marathon in less than two hours.

Before the run, much of the publicity had focused on Nike’s spring loaded Vaporfly Elite running shoe, which they had claimed improves running efficiency by as much as 4%. However in the days afterwards much of the conversation turned to aerodynamics, and the influence of the unfeasibly large timing board that was mounted on top of the pace car that drove in front of Kipchoge, and the “delta formation” adopted by his team of “relaying” pacers. By some calculations drafting was responsible for about 1:30 of the 2:32 that Kipchoge knocked off Kimetto’s world record.

In order to determine just how much influence "aerodynamic trickery" had in getting Kipchoge within 26 seconds of the mythical 2 hour barrier, we decided to run a series of computational fluid dynamics simulations using STAR-CCM+,

The objective in auto racing is pretty simple to understand: the fastest car wins.

Easy enough, right?

Well, maybe not quite that easy. After all, car manufacturers can’t control what happens on the track during any given race, but they can put drivers in the best possible position to succeed through the design of their car.

Spark Racing Technology is well aware of this, and to gain that extra inch, that extra split second that can be the difference between exhilarating victory or humbling defeat, turned to AOTECH in search of aerodynamic expertise for its FIA Formula E Championship car.

Over the past 10 years, bat populations in the United States and Canada have been decimated by an invasive fungus called Pseudogymnoascus destructans, or pd. Millions of bats have died. Considering that they are a keystone species, losing bats and their contributions to our ecosystem could have devastating results for plants, other animals and humans. The epidemic bats are facing is akin to the massive die off of bees that’s a threat to agricultural food supplies. Understanding what is happening to bats as well as the conditions they’re exposed to is essential for us to try and find a way to reverse the epidemic.

Matthew Godo
STAR-CCM+ Product Manager
Stephen Ferguson
Marketing Director
James Clement
STAR-CCM+ Product Manager
Dr Mesh
Meshing Guru
Joel Davison
Lead Product Manager, STAR-CCM+
Ravindra Aglave
Director - Chemical Processing
Karin Frojd
Sabine Goodwin
Director, Product Marketing