Microorganisms swimming in nematic liquid crystal at finite Reynolds numbers

Based on the immersed boundary method, we numerically investigate the behaviors of microorganisms in nematic liquid crystal at finite Reynolds numbers. We demonstrate that two asymmetric swimming strokes, “kicker” and “burrower,” exhibit distinct behaviors in response to fluid anisotropy and inertia. In parallel swimming, kickers generally swim faster compared to that in Newtonian fluids, while burrowers experience a slowdown. For the perpendicular case, the situation is the opposite. We attribute this difference to the distinct interactions of strokes with liquid crystal polymer stress. Furthermore, fluid inertia significantly enhances the speed and efficiency of kickers but reduces the performance of stiff burrowers. In addition, reorientation dynamics also differs, with burrowers usually rotating faster than kickers, and inertia accelerating the reorientation of kickers while having minimal effect on burrowers.