On the convective disturbances induced by g-jitter on the space station

A numerical tool has been prepared to quickly predict the overall disturbances for the typical Microgravity Environment (MGE) on the ISS. A reference study case (that shows a large sensitivity to acceleration disturbances) is identified and numerical simulations are carried out to compare the results of the solution of the full Navier-Stokes equations with a time-dependent acceleration (that give the instantaneous time-dependent flow) with the solutions of the time-averaged field equations (Gershuni formulation), containing all the g-jitter terms (like those that identify the microgravity environment of the ISS) grouped in a single parameter. The paper shows that the overall disturbances of the thermo-fluid-dynamic field are easily evaluated assigning as input to the fluid-dynamic code a single (equivalent) frequency g-jitter (in the direct formulation) or an overall vibrational Rayleigh number (in the time-averaged formulation). The code is validated and applied to the problem of thermodiffusion in a typical metal alloy.