The utilization of microsecond dwell times allows for the detection of multiple elements within a single particle.

No abstract

In this research, the influences of modal properties of a micro cubic satellite on equivalent static loads (due to combination of quasi-static and dynamic loads during launch time) have been studied. The study shows that the magnitude of equivalent static loads can be affected by satellite effective modes and effective mass distribution along natural frequencies. Besides, when to distinct launchers with different dynamic environments candidate for launch, analytical results illustrate that sometimes the equivalent static combined load value can be higher for the launcher with smaller quasi-static loads. This phenomenon is due to effective modal mass distribution of the satellite. Consequently, a higher combined load may be occurred during launch for smaller quasi-static conditions. Furthermore, in separation phase of satellite from the launcher, the satellite modal parameters influence the magnitude of applied shock load in both axial (launch) and lateral directions, importantly. Thus the present study yields reliable input values for separation shock test which considers dynamic properties of the satellite in comparison with some standards and launcher manuals, suggest a rough estimation of shock load, neglecting the satellite structure dynamic behavior.

The effect of radial throughflow on the instability of circular Couette flow is numerically studied for a viscoelastic fluid obeying the Giesekus model. An exact solution has been obtained for the base flow using the perturbation method with the cross-flow Reynolds number serving as the small parameter. The stability of the base flow to infinitesimally small, normal-mode, axisymmetric perturbations is studied using the linear temporal stability theory. An eigenvalue problem is obtained which is solved numerically using the pseudo-spectral, Chebyshev-based collocation method. The numerical results show that for small cross-flow Reynolds numbers, there exists a critical Weissenberg number at which the flow is at its most stable state. For sufficiently large cross-flow Reynolds numbers, however, it is predicted that the flow becomes monotonically less stable when the Weissenberg number is increased. These results suggest that elasticity can be used as an efficient means for the deliberate rise of Taylor cells in rotating micro-filter separators for self-cleaning purposes of the clogged pores.

Sedimentation of a single, two-dimensional, rigid, elliptic particle in a biviscous fluid contained in a finite, closed-ended channel is studied in this work using the lattice-Boltzmann method. The main objective of the work is to numerically investigate the role played by a fluid’s yield stress on the trajectory, orientation, and terminal velocity of such a particle for different density and aspect ratios. Numerical results suggest that a new mode of settling might emerge for yield-stress fluids, which is nonexistent for Newtonian fluids. That is, a particle released from the rest state at the midplane with a prescribed, nonzero, inclination angle (with respect to the horizontal line) migrates toward the left side-wall (if the inclination angle is positive) soon after it is released but changes course after a short while and moves back toward the centerline where the voyage started. However, while for Newtonian fluids the particle eventually returns to the centerline and continues its free fall with a horizontal orientation, for yield-stress fluids, the particle might finally lodge at a specific distance away from the centerline and continue its fall assuming a nonhorizontal orientation. The offset position is predicted to be a function of the Bingham number and the density ratio but independent of the initial inclination angle.