风场中两串列球形沙粒的阻力及流场特性的数值研究

Numerical research on drag force characteristics of double spherical sands in tandem arrangement

利用数值方法对雷诺数Re≤300的风场中沿风向串列的两球形沙粒的阻力系数及流场特性进行了研究.结果表明:两串列球形沙粒,后沙粒对前沙粒的阻力系数影响不大,而前沙粒对后沙粒阻力系数的影响很大,这一影响随着两沙粒间距的增大而减小,并且两沙粒的阻力系数均逐渐趋近单颗沙粒的阻力系数;两串列沙粒的阻力系数均随流场雷诺数Re的增大而单调减小;两串列沙粒流场中,前沙粒尾涡长度大于单沙粒场的尾涡长度,后沙粒尾涡长度小于单沙粒场的尾涡长度,并且前沙粒出现流动分离的Re小于单沙粒场出现流动分离的Re,而后沙粒出现流动分离的Re大于单沙粒场出现流动分离的Re.

The drag coefficient acting on double spherical sands placed in tandem arrangement and flow patterns for Reynolds number Re≤300 were investigated.The numerical results show that the influence of the posterior sphere on the drag coefficient of the anterior one was very weak,while the influence of the anterior sphere on the drag coefficient of the posterior one was was trong.With an increase in the distance between the two spheres,such influences were becoming much weaker,and the drag coefficients of the double spheres gradually approached that of the single sphere.Besides,the drag coefficients of double spheres in tandem arrangement monotonically decreased with the increase of Reynolds number.Furthermore,the length of the trailing vortex of the anterior sphere was larger than that of the single sphere,while the length of the trailing vortex of the posterior one was smaller than that of the single sphere.The Reynolds number at which the flow separation of the anterior sphere was caught was smaller than that at which the flow separation of the single sphere was caught;while Reynolds number at which the flow separation of the posterior sphere was caught was larger than that at which the flow separation of the single sphere was caught.