In this work, an unsteady state analysis of the compression cycle of a small hermetic reciprocating compressor for domestic refrigeration was carried out. The mass and energy balances were applied to the refrigerant inside the cylinder in order to determine the mass and temperature behaviour through the compression process. A specific onedimensional model of the valves was developed to calculat...

This paper investigates the impact of small-scale unsteadiness on adjoint-based output sensitivity analysis. In particular, when iterative methods for nonlinear flows fail to converge to a steady state, it is demonstrated that the resulting sensitivity analysis can be highly inaccurate, evenwhen the unsteadiness in the outputs is small. The specific example considered is the viscous subsonic fl...

Vector fields are a common concept for the representation of many different kinds of flow phenomena in science and engineering. Methods based on vector field topology are known for their convenience for visualizing and analysing steady flows, but a counterpart for unsteady flows is still missing. However, a lot of good and relevant work aiming at such a solution is available. We give an overvie...

[1] A generalized constitutive equation for bubbly liquids is presented which successfully reproduces the expected viscosity response for both steady flows with varying capillary number Ca (a measure of the bubble deformation) and unsteady flows with varying dynamic capillary number Cd (a measure of the steadiness of the flow) previously given in separate studies. The constitutive equation is g...

The deposition efficiency of unsteady inhalation is investigated in present study by using computational fluid dynamics techniques. Comparison with steady inhalation is also discussed. The inspiratory cycle of a realistic unsteady inhalation profile was applied at the outlet of nasopharynx, which has the maximum flow rate of 40.3L/min. Aerodynamic particle sizes of 5μm and 20μm were studied in ...

We report the numerical simulations of the horizontal convection within a rectangle cavity tank at high Rayleigh numbers. The physical solution of horizontal convection depends on the spatial resolution of the meshes. The necessary mesh number N is proportion to Ra. The unstable numerical solutions are obtained asN < cRa. This power law also implies that the spatial resolution is dominated by v...

We investigate the dynamics of a vesicle in a shear flow on the basis of the newly proposed advected field (AF) method [T. Biben and C. Misbah, Eur. Phys. J. E 67, 031908 (2003)]. We also solve the same problem with the boundary integral formulation for the sake of comparison. We find that the AF results presented previously overestimated the tumbling threshold due to the finite size of the mem...

The viscous flow in the fluidic amplifier is simulated numerically based on CFD technology, and many tests have been done to verify the numerical precision. The results show that the calculated data are good agreement with the experimental data. So the numerical simulation of the viscous flow in the fluidic amplifier is accurate and reliable, and it can be applied to investigate the steady flow...