Effects of polymers on the cavitating flow around a cylinder: A Large-scale molecular dynamics analysis

TL;DR

This study uses large-scale molecular dynamics simulations to show that polymers significantly suppress cavitation around a cylinder by increasing elongational viscosity and local temperature through polymer stretching and elasticity.

Contribution

It provides detailed molecular insights into how polymers suppress cavitation, highlighting the roles of elongational viscosity and entropic elasticity.

Findings

Polymer chains suppress cavitation effectively.

Polymer stretching increases elongational viscosity.

Elastic energy from polymers raises local temperature.

Abstract

The cavitation flow of linear-polymer solutions around a cylinder is studied by performing a large-scale molecular dynamics simulation. The addition of polymer chains remarkably suppresses the cavitation. The polymers are stretched into a linear shape near the cylinder and entrained in the vortex behind the cylinder. As the polymers stretch, the elongational viscosity increases, which suppresses the vortex formation. Furthermore, the polymers exhibit an entropic elasticity owing to the stretching. This elastic energy increases the local temperature, which inhibits the cavitation inception. These effects of polymers result in the dramatic suppression of cavitation.