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

Color Maps, Vectors, Streamlines, Action!

Computation Fluid Dynamics (CFD) is synonymous with impressive 3D visualization. Learn more about the basic 3D visualization techniques in CFD and how they can help you reduce the mass of raw data from a simulation into insightful and beautiful graphics.

3D Visualization in Caedium3D Visualization in CaediumCFD simulation of a cyclone

6 Things to Consider Before Switching Turbulence Model

Turbulence modeling for the Reynolds Averaged Navier-Stokes (RANS) equations - the basis of most industrial Computational Fluid Dynamics (CFD) software - is a complex field. Trying to strike a balance between accuracy and computational efficiency has given rise to a relatively large number of different turbulence models. I am not aware of a definitive list to match turbulence models to applications - if you are, please share! With this in mind I'll share 6 suggestions before you consider switching the default turbulence model in your CFD software.

RANS Simulation of Air Flow Around a ChimneyRANS CFD Simulation of Air Flow Around a ChimneyUsing the k-omega SST turbulence model

CFD Simulation Steering

You've already heard some of the advantages of using co-processing over after-the-fact post-processing, but there's more. Co-processing is an enabler of Computational Fluid Dynamics (CFD) simulation 'steering', i.e., making changes to the simulation while it is active.

CFD Simulation Steering in CaediumCFD Simulation Steering in CaediumRelaxation factors changed at 200 iterations

Why Compromise with Browser-Based CAD/CAE Applications?

Why is there an ongoing effort to cram rich interactive 3D CAD/CAE applications into a web browser for desktop and laptop computers yet there is a proliferation of dedicated apps on tablets and smart phones?

Avoid CFD Transient Data Overload with Co-Processing

Computational Fluid Dynamics (CFD) has the potential to overwhelm any computer, including the largest super computers, with generated flow field data (e.g., pressure, velocity) for transient (time dependent or time accurate) simulations. The traditional approach to transient simulations, and still widely used today, is to run a transient simulation and store entire flow field data sets at each time step for post processing at a later date. Given that a transient simulation can run for 10,000s of time steps, data management clearly becomes a significant issue, or more often a headache. However, there is an elegant alternative - co-processing.

CFD Co-Processing for a Transient Simulation in CaediumCFD Co-Processing for a Transient Simulation in Caedium

5 Tips for CFD Flow Volume Creation

Configuring a flow volume for Computational Fluid Dynamics (CFD) is often the most difficult task during the simulation process. Follow these 5 tips to make your CFD flow volume creation less painful.

3D Model With Too Much Detail For CFD3D Model With Too Much Detail for CFD

CFD Flow Volumes and Solid Models

Solid modeling is the dominant form of virtual object representation underpinning nearly all 3D Computer-Aided Design (CAD) systems. The strength of a solid model is that it defines a water tight (manifold) unambiguous object which implicitly delineates between the inside and the outside of an object simply by the alignment of the boundaries (B-rep or BREP) that define it. This makes solid modeling an ideal basis for virtual analysis techniques, e.g., stress analysis and Computational Fluid Dynamics (CFD). Also solid modeling provides a relatively straightforward path to manufacture through CNC machines and, more recently, 3D printing.

Cylinder Head Solid ModelCylinder Head Solid ModelBoundary Representation (B-rep or BREP)

Sports, Fluid Flow, and Spheres

Given how easy it is to define a sphere with a single value (radius) you'd think the fluid flow around a sphere would be simple too, right? However, as with many innocuous looking fluid problems, our intuition is wrong. The resulting flow characteristics, especially the drag variation with fluid velocity, are wild. Why does this matter? One word - sports.

CFD Simulation of Flow Around a SphereCFD Simulation of Flow Around a SphereReynolds number 10,000, large unsteady asymmetric recirculation

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