Complex Fluids Lab

The Complex Fluids Lab led by Dr. Ping He focuses research on the computational fluid dynamics aiming to solve grand challenges involved with complex interfacial phenomena and thermal processes.

 

Instruments:

High-Performance Computing Cluster

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A general-purpose high-performance computing cluster that features:

  • 44 compute nodes of 1,584 CPU cores in total
  • Intel Xeon E5-2695 v4 CPU x 2 per node (36 cores per node)
  • 100Gb/s Intel Omni-Path Fabric, and 1Gb/s Ethernet
  • 128GB of memory per node
  • 50TB of RAID storage, and 50TB backup storage
  • Peak performance of 53.2 TFlops

 

Projects

Wetting Phenomena on Homogeneous and Heterogeneous Substrates

This project develops a state-of-the-art simulation tool for modeling realistic wetting dynamics of liquid droplets on homogeneous as well as heterogeneous solid surfaces. This research also establishes an experimentally validated slip boundary model on the liquid-gas-solid contact line. The outcomes of this study are critically helpful to the design of meta-materials in wetting and de-wetting applications.

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Wetting on oil-infused substrates

The wetting phenomenon on oil-infused substrates is a heterogeneous wetting condition in a solid-liquid-liquid-gas system, where lubricant oils are used to infuse rough solid surfaces to reduce the friction and enhance heat transfer for liquid (usually water) droplets interacting with oil and solid. A new continuum surface force model is being developed for the balance of surface tensions in three fluid phases. Static and dynamic behaviors of the wetting process have been validated through experimental results available in the open literature. The interactions of two droplets are being investigated.

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Figure. Merging of two water droplets, whose flattened diameter is around 100 µm, on a film of lubricant oil.

 

Computational Fluid Dynamics of Pilot-wave Hydrodynamics

French researchers Couder et al. first reported that the walking droplets on a Faraday wave behave analogously to single particle quantum systems. The vibrating fluid bath generates the Faraday wave in the absence of droplets, and interacts with droplets into bouncing or walking modes. Modeling and simulations are limited in semi-analytical, decoupled conditions. This research tackles this problem using a full fluid dynamics approach to understand the following questions:

How does a continuum system exhibit quantum behaviors, which are previously only found in the sub-atomic and photonic conditions? Will this continuum-quantum analogy enable the fluid dynamics to be a powerful tool to re-examine quantum physics?

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Figure. Preliminary results of pilot-wave dynamics simulation: (a) before walk, and (b) in walk. Color coding presents the vertical velocity field (m/s).