Speed Up CFD with Symmetry and Cyclic Conditions

Symmetry (or planar symmetry) and cyclic (or rotational symmetry) boundary conditions for Computational Fluid Dynamics (CFD) can often save you 50% or more in simulation turnaround time. Alternatively you can use the freed up memory to run more accurate simulations with more mesh cells clustered in areas of interest. Clearly these simulations are worth considering if your model satisfies the symmetry or cyclic criteria.

Symmetric Flow Volume for the External Aerodynamic CFD Analysis of a CarSymmetric Flow Volume for the External Aerodynamic CFD Analysis of a CarSingle symmetry plane

Airships Rising

Airships are enjoying a renaissance of sorts. Military forces have proposed airships for surveillance and heavy lift duties. A small number of impressive prototypes have already taken to the air, but little follow-on development seems imminent. Could this renaissance be just a bli(m)p?

CFD Simulation of Flow Around an AirshipCFD Simulation of Flow Around an Airship

World Cup Stadium Aerodynamics with CFD

The 2014 FIFA World Cup is well underway and the final match to crown the world champions will be played in the Maracanã Stadium. The stadium was originally built to host the 1950 World Cup final, but with the stadium being the focal point for the current 2014 World Cup and the upcoming 2016 Olympics it was deemed that it needed a revamp. The most striking difference between the old and newly renovated stadium is the roof that now protects 95% of the seating from rain and provides better shade. The original roof only offered minimal rain protection and shade to a few rows of seats. However, it seems little air-time has been devoted to analyzing the wind characteristics of the playing area inside the stadium due to the different roof extents, especially when you consider how much attention the aerodynamics of the match ball have garnered. Rest easy though, Computational Fluid Dynamics (CFD) is here to help.

Caedium CFD Simulation of a StadiumCaedium CFD Simulation of a StadiumStreamlines

World Cup Balls

Every 4 years the FIFA World Cup rolls around and the question on everyone's lips will the official match balls behave? Oh, and to a lesser degree, which nation will win?  Ball aerodynamics are complex, but relatively well understood. Given the typical speed and spin of balls in the beautiful game, small changes to their surface texture (the focus of much recent effort in ball design) can have dramatic repercussions on their trajectories and hang times. Balls are deemed so important that each has its own Wikipedia page and each has tournament-flavored names thanks to Adidas, the long time ball designer.

CFD Simulation of Flow Around a Rotating BallCFD Simulation of Flow Around a Rotating Ball

Tower Bridge Meets CFD

Complete, watertight, complex geometry is a rare but welcome find in Computational Fluid Dynamics (CFD). However, thanks to the steering committee of the upcoming 23rd International Meshing Roundtable, such a geometry, in various formats, is freely available for their meshing contest. The star of the contest is London's Tower Bridge, I presume in honor of the conference's host city. So to the bat cave to see what Caedium Professional can do with this model.

Tower Bridge Caedium CFD SimulationTower Bridge Caedium CFD SimulationVelocity contours

How to Make a Splash in CFD

It is a common occurrence: a rain drop falls into a puddle; a leaky faucet drips into a sink of water. This seemingly simple event has some complex physics in play that advanced multi-phase, free-surface (volume of fluid - VOF) Computational Fluid Dynamics (CFD) can simulate. Not only can CFD simulate water impact in a pool, it can also produce a beautiful 3D visualization of the process as an animation. Follow along to see how you can use Caedium Professional to simulate a water droplet falling into a pool of water.

VOF Free Surface Caedium CFD SimulationVOF Free Surface Caedium CFD SimulationDroplet crater

Caedium CFD Sneak Peek: Passive Species Transport

The next release of the Caedium CFD software system will be able to simulate the convection and diffusion of a passive species, also known as a passive scalar. A passive species can represent and track additions such as smoke in airflow and dye in water. It can also provide insights on the dispersion of pollutants carried by a fluid.

Caedium Passive Species CFD SimulationPollutant plume released in air from a chimney

Automated Creation and Export of CFD Results

Previously I showed how to automate a sequence of Caedium Computational Fluid Dynamics (CFD) simulations of an alpha sweep for an airliner. Next up I will show you how to automate the export of results from Caedium in a specific format. This example focuses on the files required for ixCube 4-10 (the successor to ixForten 4000) to perform a structural analysis using the pressure coefficient (Cp) from an airflow simulation over a tensile structure or membrane.

Caedium Membrane CFD SimulationCaedium Membrane CFD Simulation

Aerodynamics Plays No Role in the Performance of Stationary Bicycles

While I'm sure you know aerodynamics does play a crucial role in outdoor cycling, aerodynamics doesn't offer any performance gains for stationary cycling indoors. With this in mind, hopefully you spotted that my previous blog post "Aerodynamic Performance of a Stationary Bicycle" was a cunning April Fools' Day ruse.

Stationary Bicycle StreamlinesStationary Bicycle StreamlinesNo airflow, no streamlines

Aerodynamic Performance of a Stationary Bicycle

Aerodynamics plays a crucial role in the performance characteristics of outdoor cycling. However, no-one to my knowledge has used Computational Fluid Dynamics (CFD) to analyze the aerodynamic performance of a stationary bicycle - at least until now!

SketchUp Model of a Stationary Bicycle and CyclistSketchUp Model of a Stationary Bicycle and Cyclist

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