Flow enhancement of deformable self-driven objects by countercurrent

• Published in: Physics letters. A Vol. 380; no. 42; pp. 3490 - 3496
• Main Authors: Mashiko, Takashi, Fujiwara, Takashi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 14.10.2016
• Subjects: Countercurrent; Deformable object; Transport system; Countercurrent; Deformable object; Transport system
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2016.08.052

We report numerical simulations of the mixed flows of two groups of deformable self-driven objects. The objects belonging to the group A (B) have drift coefficient D=DA (DB), where a positive (negative) value of D denotes the rightward (leftward) driving force. For co-current flows (DA,DB>0), the result is rather intuitive: the net flow of one group (QA) increases if the driving force of the other group is stronger than its own driving force (i.e., DB>DA), and decreases otherwise (DB<DA). For countercurrent flows (DB<0<DA), however, the result appears paradoxical: the net flow of one group (QA) can increase with the driving force of the other group (|DB|), and the net flow with a stronger countercurrent can be larger than the net flow with a weaker co-current. This phenomenon is observed only for deformable objects and results from the entanglement of objects, which in turn is caused by their deformability. •Mixed flows of two groups of deformable self-driven objects are simulated.•The net flow of one group can increase with the strength of the countercurrent.•The net flow with a countercurrent can be larger than that with a co-current.•This results from the individual deformability, via the entanglement of objects.