Dissipative Particle Dynamics

Dissipative Particle Dynamics (DPD) is a mesoscale modelling method based on calculating forces on particles and integrating them over a discrete time step to evolve particle positions and velocities. The main feature of DPD is a special pairwise thermostat, that controls the system temperature while maintaining momentum conservation to ensure correct hydrodynamics. The interactions between DPD particles (‘beads’) are generally soft and repulsive - representing large collections of atoms/molecules or a fluid continuum - which allows longer times to be achieved with fewer time steps than ordinarily available with atomistic molecular dynamics.

To give you an overview of DPD’s capabilities, I have put together a few exercises making use of the CCP5 code package DL_MESO. These exercises can all be run on standalone desktops or laptops - while these involve fairly small simulation sizes, they cover several features available with DPD.

We strongly recommend that:

  1. you first read and follow the instructions to download and compile DL_MESO’s DPD code and utilities in Setting up DL_MESO;
  2. you take a look at Intro to Dissipative Particle Dynamics as well as the details on using DL_MESO’s DPD code in Using DL_MESO_DPD; and
  3. you complete at least the first two exercises, as these cover the main features of DPD based on how it is frequently used.

The third exercise is less essential but gives greater insight into how DPD could be used for a wider range of applications. Please do not worry if you cannot complete all three exercises today: these can be provided for you to take home and complete later.

The more detailed explanations of the theoretical background to the exercises are also not absolutely essential to complete the exercises, but they might be useful for providing more context on how and why DPD works.

If you need any assistance on these DPD exercises after today, please email your questions to Michael Seaton.