Fluctuation-induced forces in homogenous isotropic turbulence

In this talk, we uncover a fluctuation-induced force between two plates immersed in homogeneous isotropic turbulence using Direct Numerical Simulations. The force is a non-monotonic function of plate separation. The mechanism of force generation reveals an intriguing analogy with fluctuation-induced forces: energy in the fluid is localised in regions of high vorticity, or "worms", which have a characteristic length scale. The magnitude of the force depends on the packing of worms inside the plates, with the maximal force attained when the plate separation is comparable to the characteristic worm length. We explore the effect of different plate sizes and shapes on the force, as well as in more generalised objects. We ask the question whether these "worms" can induce other fluctuation forces on asymmetrical objects.