Celeris-WebGPU theory, source code

The WebGPU version of Celeris solves the enhanced Boussinesq equations of Madsen & Sørensen or the fully nonlinear extended Boussinesq equations with a modern Finite Volume scheme. Details of the numerical approach, etc can be found here: Lynett, P. et al (2025). Celeris-WebGPU: An Interactive Nearshore Wave Simulator for Engineering Design and Natural Hazard Education. In review, Waterways. https://www.dropbox.com/scl/fi/3jxuxmgh9yd63if8u8yo6/WebGPU-Paper_InReview.pdf?rlkey=3mcroqzl687z8idfotjjyrw1v&dl=0

Tavakkol, S., & Lynett, P. (2017). Celeris: A GPU-accelerated open source software with a Boussinesq-type wave solver for real-time interactive simulation and visualization. Computer Physics Communications, 217, 117-127.

https://www.sciencedirect.com/science/article/abs/pii/S0010465517300784

and here:

Tavakkol, S., & Lynett, P. (2020). Celeris base: An interactive and immersive Boussinesq-type nearshore wave simulation software. Computer Physics Communications, 248, 106966.

https://www.sciencedirect.com/science/article/abs/pii/S0010465519303169

Additions to the Celeris physics engine with the WebGPU implementation include:

Kennedy et al breaking model
Advection-dispersion model for transport of breaking-created foam
Updated moving boundary scheme for accuracy and stability
Passive pollutant transport
Spatially varying friction models, and user interactivity to place friction components
Sediment transport model (under development)
Ship-generated waves (under development)

In general, the sequence of the solver follows that of previous implementations. With WebGPU, the control file has been written in Javascript, and all shaders converted to wgsl. The source code can be found here: https://github.com/plynett/plynett.github.io

2 comments

Comments (2)

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José Galaz

Aug 21

Hello Patrick, thanks for sharing this preprint, it is very interesting and helpful for understanding.

Do you have an example on how to setup the initial distribution of the passive scalar transport model?

Patrick Lynett

Sep 01

Replying to

Hi Jose- Unfortunately, I do not. I should put together a short tutorial. In the meantime, once you have a simulation running, you can add with these steps: 1) In the Modify Visualization panel, change the Transport Overlay to Passive Tracer Conc 2) Then in the Modify Sea Level & Edit Bathy/topo, change the Property to Edit to Passive Tracer Sources and Set Value to Click on the dropdown below (Change Property Continously....) 3) Change the lengthscale of the tracer source you want, and then click on the canvas to place it. The model adds a constant concentration source where you clicked, and you should see the tracer advect / diffuse away from that spot. 4) You can change the turbulent dispersion of the scalar in the Modify Simulation Parameters panel - look for Turbulent Dispersion That should get you started. Its a bit of a hack, as you can see. Right now the breaking "foam" and the scalar transport are using the same channel in a texture, so you can only show one or the other.