Design of aerial vehicles and weapon systems relies on the ability to predict aerodynamic behavior, often aided by advanced computer simulations of the flow of air over the body. High-fidelity simulations assist engineers in maximizing how much load a rotorcraft can lift or how far a missile can fly, but these simulations aren’t cheap. A new turbulence model could change that.
The simulations that designers currently use require extensive data processing on supercomputers and capture only a portion of vortex collision events — which can cause significant performance degradation, from loss of lift on a rotor to complete loss of control of a munition. A new turbulence model could change that.
The Army Research Office, an element of the U.S. Army Combat Capabilities Development Command, now known as DEVCOM, Army Research Laboratory, funded researchers at Purdue University to advance a turbulence model known as the Coherent-vorticity-Preserving Large-Eddy Simulation, known as CvP LES. Published in the Journal of Fluid Mechanics, the new methodology simulates the entire process of a vortex collision event up to 100 times faster than current state-of-the-art simulation techniques.
«The thing that’s really clever about Purdue’s approach is that it uses information about the flow physics to decide the best tactic for computing the flow physics,» said Dr. Matthew Munson, Program Manager for Fluid Dynamics at ARO. «There is enormous potential for this to have a real impact on the design of vehicle platforms and weapons systems that will allow our Soldiers to successfully accomplish their missions.»
The fluid dynamics of aircraft turbulence are complex, and simulating them accurately in the computer is nearly impossible. Prof. Carlo Scalo has taken a leap forward in this process, by modeling the collision of vortices in two ways: once with direct numerical simulation, and once with large-eddy simulation. This model can now be used by engineers to design better aircraft, without having to wait months for supercomputer calculations. Carlo Scalo’s Compressible Flow and Acoustics Lab: Mechanical Engineering:
The model can be used to simulate vortices over any length of time to best resemble what happens around an aircraft. For instance, as a rotor blade moves through the air, it generates a complex system of vortices that are encountered by the next blade passage. The interaction between the blade and the vortices can lead to vibration, noise, and degraded aerodynamic performance. Understanding these interactions is the first step to modifying designs to reduce their impact on the vehicle’s capabilities.
Story Source: Materials provided by U.S. Army Research Laboratory. Note: Content may be edited for style and length.