196 research outputs found
Mesoscale simulation model for odd fluids
No full textA fluid, with broken time-reversal symmetry, would exhibit odd transport coefficients, such as odd viscosity, thermal conductivity and diffusion coefficient, which may fundamentally alter the fluid properties and significantly influence the structure and dynamics of immersed objects. Here, we develop an efficient coarse-grained simulation approach for the odd fluid, that captures all essential features of real odd fluids. Based on microscopic kinetic theory, we analytically derive the transport coefficients of the mesoscale odd fluid. Furthermore, we validate our approach by performing both simulations and theoretical calculations to explore the intricate transport phenomena of the odd fluid under various external drivings. Our work thus paves the way for studying anomalous transport in odd fluids and for large-scale simulations of odd complex fluids.6 pages, 4 figure
Thermoosmotic microfluidics
No full textMicrochannels with asymmetrically ratcheted walls are here shown to behave as effective and versatile microfluidic pumps if locally heated. When the boundary walls have different temperatures, the confined liquid experiences a temperature gradient along the sawtooth edges, which can induce a thermoosmotic flow. A mesoscale molecular simulation approach is here employed to investigate the flows which are contrasted using an analytical approach. Microchannels can be composed by one or two ratcheted walls which can be straight or cylindrical. Varying the channel geometry can not only change the overall fluid flux, but also vary the flow patters from shear to capillary type, or even to extensional type flows. This scheme does not require multiphase fluids or any movable channel parts, although they are possible to be implemented. The proposed principle is then very versatile to locally manipulate complex fluids, and a promising tool to recover waste heat, to facilitate cooling of microchips, and to manufacture portable lab-on-a-chip device
Research on Linux Real-time Mechanism and Classified Scheduling Strategy of Handheld Terminal
No full textAccording to the high real-time performance and multitasking features of the handheld terminal,some real-time mechanisms are added to the kernel,such as real-time mutual exclusion lock,threaded interruption,high precision timer and dynamic clock.Based on the idea of the RM algorithm combined with SCHED_FIFO algorithm,a taskset classified scheduling strategy is proposed.Considering the deadline scheduling algorithm has the feature of high hard real-time performance,deadline scheduling algorithm is used to schedule hard real-time task and real-time group scheduling algorithm is used to schedule soft real-time task.Theoretical derivation and experimental results show that the real-time performance of the improved Linux kernel meets the microsecond requirements of hard real-time tasks,and it also can reduce the tasks’ deadline missing rate effectively when the system is overloaded.The average deadline missing rate is dropped by 18% when CPU load range is between 1.2 and 2.8
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