فهرس المقالات داود طغرایی


  • المقاله

    1 - Study Effect of Deformation Nanochannel Wall Roughness on The Water-Copper Nano-Fluids Poiseuille Flow Behavior
    Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering , العدد 1 , السنة 8 , زمستان 2015
    In the nanochannel flow behavior with respect to expand their applications in modern systems is of utmost importance. According to the results obtained in this study, the condition of nonslip on the wall of the nanochannel is not acceptable because in the nano dimension أکثر
    In the nanochannel flow behavior with respect to expand their applications in modern systems is of utmost importance. According to the results obtained in this study, the condition of nonslip on the wall of the nanochannel is not acceptable because in the nano dimensions, slip depends on different parameters including surface roughness. In this study, keeping the side area roughness, deformation effects on fluid flow behavior is investigated. Modeling software open source LAMMPS with equilibrium molecular dynamics simulations have been carried out. Unlike previous studies, existence fluid in laboratory conditions as water-copper nanofluids used. The results showed that rectangular was the most effective and triangular was least effective roughness on flow behavior, resulting in a rough triangular nanochannel slip occurs with more intensity.Existence roughness on the surface increases the number of oscillations in the fluid layer but amplitude near the wall is smooth to rough increased. Nanoparticles also increase the impact on the flow properties تفاصيل المقالة

  • المقاله

    2 - Longitudinal Wave Propagation Analysis of Stationary and Axially Moving Carbon Nanotubes Conveying Fluid
    Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering , العدد 2 , السنة 8 , بهار 2015
    In this study, the effect of small-scale of both nanostructure and nano-fluid flowing through it on the natural frequency and longitudinal wave propagation are investigated. Here, the stationary and axially moving single-walled carbon nanotube conveying fluid are studie أکثر
    In this study, the effect of small-scale of both nanostructure and nano-fluid flowing through it on the natural frequency and longitudinal wave propagation are investigated. Here, the stationary and axially moving single-walled carbon nanotube conveying fluid are studied. The boundary conditions for the stationary nanotube is considering clamped-clamped and pined-pined and for the axially moving SWCNT is simply supported end where the left-end has been restrained. To apply the nano-scale for fluid the Knudsen number and to apply the structure the nano-rod model and nonlocal theory are utilized. Next, using the approximate Galerkin method the governing equation of motion is discretized and solved. In addition, the ratio of the natural frequency and phase velocity to the wave number and also the influence of velocities of flowing fluid and axially moving structure on the natural frequency would be studied. It can be shown that the natural frequency and wave propagation velocity are depending to the nano-scale of the structure and fluid flowing through it. So that, by increasing the nonlocal parameter, the natural frequency is decreased and by increasing the Knudsen number the system frequency is increased hence, leading to a bigger wave تفاصيل المقالة