Angular Velocity of Kolmogorov-Scale Fibers as Proxy for Turbulent Dissipation

We introduce a fiber-based method to directly measure turbulent energy dissipation. Combining original measurements of the full-body rotation—tumbling and spinning—of short, Kolmogorov-scale fibers in turbulent channel flow with direct numerical simulations using a point-fiber model, we show that the mean-square angular velocity closely reproduces the mean dissipation rate. The method is accurate both in the nearly homogeneous turbulence of the channel center and in the logarithmic layer, with a mean deviation below 6%, demonstrating that Kolmogorov-scale fibers provide a robust and reliable tool for quantifying dissipation.