To help design aircraft that can better maneuver in extreme situations, researchers have developed a modeling approach that simulates the entire process of a vortex collision at a reduced computational time. This physics knowledge could then be incorporated into engineering design codes so that the aircraft responds appropriately.
The simulations that aircraft designers currently use capture only a portion of vortex collision events and require extensive data processing on a supercomputer. Not being able to easily simulate everything that happens when vortices collide has limited aircraft designs. With more realistic and complete simulations, engineers could design aircraft such as fighter jets capable of more abrupt maneuvers or helicopters that can land more safely on aircraft carriers.
Engineers would still need a supercomputer to run the model but they would be able to simulate a vortex collision in about a tenth to a hundredth of the time using far less computational resources than those typically required for large-scale calculations.
The model is a Coherent-vorticity-Pre-serving (CvP) Large-Eddy Simulation (LES) capable of capturing complex physics without having to wait a month on a supercomputer. The researchers conducted complex, large-scale computations to prove that the model is accurate. These computations allowed them to create a more detailed representation of the problem using more than a billion points. For comparison, a 4K ultra-high-definition TV uses approximately 8 million points to display an image.
Building off of this groundwork, the researchers applied the CvP-LES model to the collision events of two vortex tubes called trefoil knotted vortices that are known to trail the wings of a plane and “dance” when they reconnect. It is very hard computationally to simulate because it is an intense localized event that happens between two structures.
The team processed data on the thousands of events that take place when these vortices dance and built that physics knowledge into the model. They then used their turbulence model to simulate the entire collision dance. Engineers could simply run the ready-made model to simulate vortices over any length of time to best resemble what happens around an aircraft. Physicists could also shrink the model down for fluid dynamics experiments. The team is working with the Department of Defense to apply the CvP-LES model to large-scale test cases pertaining to rotorcrafts such as helicopters.