Simulation as a service

It is, so to speak, rocket science. Designing aircraft, drones and missiles calls for insights into how air flows past their bodies. Parts of an aircraft, especially the airfoil, need to be carefully designed as conditions might occur beyond an angle – that is, the critical angle of attack – above which an aircraft can't rise. Commercial and military aircraft seek to stay away from these conditions known as stall conditions; so, it is imperative to find the critical angle.

It is hard to simulate this, as airflow starts separating from the wing at this angle between the airfoil and the ambient airflow. But Sankhya Sutra Labs, a spin-off from the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, has developed high-fidelity novel computational algorithms to simulate such aerodynamic problems. Instead of considering the fluid as a collection of particles, it models them via probability density functions, which represent crowds of molecules at any position moving with the same velocity.

To simulate fluid density in a computer, scientists construct space in the form of a lattice. Through equations, they calculate fluid properties at minutely spaced lattice points, collectively mimicking fluidic behaviour. Arranging such points in a body-centred cubic structure, Sankhya Sutra researchers found an order-of-magnitude increase in their methods' efficiency.

This new formulation aids in simulating turbulence, the holy grail of aerodynamics. Scientists at the Bengaluru-based company, now a subsidiary of Reliance Industries Ltd, identify small whirlpool-like motions, or eddies, within a turbulent flow and attempt to resolve them individually. These eddies are of various dimensions, so resolving them would depend upon how small a lattice point one takes.

"The question is: How do you take care of the eddies that you are ignoring as these would be the ones that would incur inexactitudes in simulations," says Vinay Kariwala, Vice President, Business Development, Sankhya Sutra Labs.