Free and Forced Oscillations of Magnetic Liquids Under Low-Gravity Conditions

Abstract

The sloshing of liquids in microgravity is a relevant problem of applied mechanics with important implications for spacecraft design. A magnetic settling force may be used to avoid the highly non-linear dynamics that characterize these systems. However, this approach is still largely unexplored. This paper presents a quasi-analytical low-gravity sloshing model for magnetic liquids under the action of external inhomogeneous magnetic fields. The problems of free and forced oscillations are solved for axisymmetric geometries and loads by employing a linearized formulation. The model may be of particular interest for the development of magnetic sloshing damping devices in space, whose behavior can be easily predicted and quantified with standard mechanical analogies.

Total magnetic force on a ferrofluid droplet in microgravity

“…This set of perturbed parameters and variables is fed into Eqs. (22) to (24) to obtain the droplet position and acceleration. The droplet tracking system error is finally determined by computing the standard deviation of the full Monte Carlo dataset for the desired variables.…”

StELIUM: A student experiment to investigate the sloshing of magnetic liquids in microgravity

“…Only the magnetic field intensity and actuation frequency vary between drops and, as described in Ref. (35), the sloshing frequencies vary accordingly. The structural configuration of the system is maintained throughout this process.…”

“…Experimental works on linear liquid sloshing have historically focused on the measurement of oscillation frequencies and modal shapes for different tank geometries and gravity levels (4; 6; 8). As previously stated, the sloshing of magnetic liquids in microgravity can be studied by assuming small oscillations through modal analysis (35). The design of StELIUM is consequently based on this methodology and has the following objectives:…”

“…Each union is composed of an inner plastic bearing located inside an aluminum holder. The properties of the plastic ring are assumed to be similar to the Igus Iglide J 1 , whose maximum recommended surface pressure is 35 MPa. An encastre boundary condition is applied to the upper face of the plastic ring to simulate the presence of the rail.…”

“…2017 experimental campaign measured the axisymmetric sloshing of ferrofluids when subjected to an inhomogeneous magnetic field in microgravity (32; 33; 34). Quasi-analytical magnetic sloshing models (35) and feasibility analyses (36) have also been presented.…”