Computation of the torque on particle aggregates and virus-like particles

In a previous paper, computational results for drag and diffusion coefficients for particle aggregates virus like particles were reported. In this work we explore similar computations for torque on particle aggregates and virus like particles. In the free-molecular regime we have used a Monte Carlo technique, and in the continuum regime we solved relevant boundary integral equations with a numerical technique. Our test results agree with those available in the literature and provide values that are exact within numerical tolerance. Furthermore, we use our results in the free-molecular and the continuum limits for the construction of approximations, including a modified Sherman approximation, applicable over the full range of Knudsen numbers. [Display omitted] •Examples of computation of torque for particle aggregates.•Examples of computation of torque for virus like particles.•Torque computations in the free molecular regime by Monte Carlo simulations.•Torque computations in the continuum regime by numerical solution of Stokes Boundary Integral Equation.•Exploration of approximations useful for all particle sizes and Knudsen numbers.