iTurbo vs Make Chirps

This application performs a Direct Numerical Simulation (DNS) where the Navier-Stokes equations are solved for two dimensional incompressible homogeneous turbulence. These equations are a set of nonlinear partial differential equations. The time stepping is performed with a simple Euler method where the time step is calculated so that the CFL number does not exceeds the given number (should be less than 0.8 otherwise the simulation blows up). The equations are solved in the Fourier space where the calculation of the nonlinear term transforms to a simple multiplication. The main CPU usage is consumed by transforming the vorticity field back and fourth between the Normal space where the time-stepping is performed and the Fourier space where the nonlinear term is calculated.

This educational app displays gravitational wave chirps created by mergers of massive black holes in several different ways, giving users an intuitive understanding of these exotic disturbances of space-time itself produced by cataclysmic events in distant galaxies. FEATURES: • Simulation: Experience the intricate behavior of gravitational waves through physics simulation of inspiralling black holes that merge to form a final black hole which then “shakes off” its excess energy. • Visualizations: See the essence of gravitational waves via waveform plots, frequency evolutions, and spectrograms, to understand the patterns and how they depend on black hole masses. • Auditory Experience: Listen closely as you hear the evolution of gravitational waves, detecting the characteristic increase in time in strength and frequency. Try varying masses to see how pitch is affected. • Dynamic Animations: Witness the captivating dance of black holes in collision animations. Explore the propagation of these waves through space-time with mesmerizing spiral animations. • Educational Insights: Gain a comprehensive understanding of gravitational waves and the pioneering work of LIGO through informative text pages, enhancing your knowledge of these cosmic phenomena. COMPATIBILITY Compatible with iPhone and iPad, iOS 16 or later. ACKNOWLEDGEMENT Supported by the National Science Foundation with grant PHY-2110181.