Leite L R, Lucena D, Potiguar F Q, Ferreira W P
Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Campus dos Palmares, 62785-000 Acarape, Ceará, Brazil.
Universidade Federal do Ceará, Departamento de Física Caixa Postal 6030, 60455-760 Fortaleza, Ceará, Brazil.
Phys Rev E. 2016 Dec;94(6-1):062602. doi: 10.1103/PhysRevE.94.062602. Epub 2016 Dec 2.
Depletion forces exerted by self-propelled particles on circular and elliptical passive objects are studied using numerical simulations. We show that a bath of active particles can induce repulsive and attractive forces which are sensitive to the shape and orientation of the passive objects (either horizontal or vertical ellipses). The resultant force on the passive objects due to the active particles is studied as a function of the shape and orientation of the passive objects, magnitude of the angular noise, and distance between the passive objects. By increasing the distance between obstacles the magnitude of the repulsive depletion force increases, as long as such a distance is less than one active particle diameter. For longer distances, the magnitude of the force always decreases with increasing distance. We also found that attractive forces may arise for vertical ellipses at high enough area fraction.
利用数值模拟研究了自驱动粒子对圆形和椭圆形被动物体施加的耗尽力。我们表明，活性粒子浴可诱导出对被动物体（水平或垂直椭圆）的形状和取向敏感的排斥力和吸引力。研究了活性粒子对被动物体产生的合力与被动物体的形状和取向、角噪声大小以及被动物体之间距离的函数关系。只要障碍物之间的距离小于一个活性粒子直径，通过增加障碍物之间的距离，排斥耗尽力的大小就会增加。对于更长的距离，力的大小总是随着距离的增加而减小。我们还发现，在足够高的面积分数下，垂直椭圆可能会产生吸引力。
