Published August 31, 2016

Mathematical Acrobatics

Clayton Grow

Senior Research Engineer

The Swinging Sticks or Chaos Pendulum is the latest addition to the Convergent Science headquarters.

ChaosSticks-CSI-3This kinetic sculpture embodies the essence of what makes CONVERGE CFD software unique: we can efficiently simulate chaos. Our CFD solver is mathematically and physically robust, and we allow the solver to predict where the mesh refinement is needed most.

Just like the Swinging Sticks, fluid flow in real-life, unsteady systems is complex and can be unpredictable. But just like the simplicity of the sculpture, CONVERGE provides you with a way to simulate chaos using a very simple set of input parameters.

A few weeks ago, this unrepeatable pattern concept was at the heart of a riveting company-wide discussion about cycle-to-cycle variation in unsteady systems. In a physical system, flow phenomena can vary from experiment to experiment, even when all of the initial conditions are identical, due to slight physical perturbations that grow and induce a larger effect on the flow as they propagate through the fluid domain. Some call this the butterfly effect.

Our discussion focused on how numerical perturbations can have this same effect on an unsteady system. These numerical perturbations can be caused by seemingly negligible rounding differences or changes to a random number seed. We are highly encouraged by our ability to predict this cycle-to-cycle variation in unsteady systems.

Despite how dry and technical “cycle-to-cycle variations in unsteady systems” sounds, the conversation was truly fascinating. Being in that room with a few dozen passionate PhDs, mechanical engineers, and CFD specialists was one of the most thought-provoking experiences I’ve ever had.

If your application requires you to predict complex and unsteady fluid flow behavior, we can help you. Email me at [email protected] if you’d like to see what CONVERGE CFD can do for you.