---
license: mit
viewer: false
---

# Description 

This dataset contains a set of example simulations using [diffSPH](https://github.com/tum-pbs/diffSPH). A dataloader and further information is available as part of _diffSPH_.


# Simulation Setup

The general simulation setup:
- Domain Size: $1[m]\times 1[m]$ ($[-0.5, 0.5]^2$)
- Particle Count: $128 \times 128 = 16384$
- Particle size: $1/ (128\times 128) = 0.000061035[m^2]$
- Neighborhood Size: $45.228$ neighbors per particle
- Rest Density: $1 [kg/m^2]$
- Timestepping: Fixed $\Delta t = 1 [ms]$
- Integration Scheme: Symplectic Euler for WCSPH, RK2 for compressible SPH
- SPH Formulation: $\delta^+$-SPH for WCSPH, CRKSPH for compressible SPH
- Shifting Scheme: $\delta^+$-SPH for WCSPH only
- Boundary Handling Scheme: MDBC
- Viscosity: $\delta^+$-SPH, $\operatorname{Re}=2000$


# Data Layout:

Each simulation is stored as a single hdf5 file with meta information available about the simulation configuration and parameters. Each timestep is a seperate group under the simulationData group. For more information on how to process the data, see _diffSPH_. To load the data using diffSPH you can simply:

```py
import torch
import matplotlib.pyplot as plt
import warnings
from tqdm import TqdmExperimentalWarning
warnings.filterwarnings("ignore", category=TqdmExperimentalWarning)
from tqdm.autonotebook import tqdm
from diffSPH.plotting import visualizeParticles, updatePlot
from diffSPH.operations import sph_op
from diffSPH.kernels import getSPHKernelv2

from diffSPH.dataLoader import *
from BasisConvolution.convLayerv3 import BasisConvLayer

configuration = DataConfiguration(
    frameDistance=1,
    frameSpacing=1,
    maxRollout=1,
    historyLength=1,
    skipInitialFrames=0,
    cutoff=0
)
folder = './data/compressible/circleCase'


processed = processFolder(folder, configuration)

for file in processed:
    print(f'File: {file["fileName"]}, FrameCount: {len(file["frames"])}, Samples: {len(file["samples"])}, Style: {file["style"]}, Number of samples: {len(processed[0]["samples"])}, first sample: {processed[0]["samples"][0]}, last sample: {processed[0]["samples"][-1]}')

dataset, datasetLoader = getDataLoader(processed, 4, shuffle = True)
datasetIter = iter(datasetLoader)
nextData = next(datasetIter)

priorStates, currentState, trajectoryStates, domains, rotMats, configs, neighborhoods = loadAugmentedBatch(
    dataset, nextData, configuration, device = 'cuda', dtype = torch.float32,
    augmentAngle = False,
)

fig, axis = plt.subplots(1, len(nextData), figsize=(len(nextData) * 4, 5), squeeze = False)
plots = []
axes = axis.flatten()
for b in range(len(domains)):
    plot = visualizeParticles(fig, axes[b],
                              particles = currentState,
                              domain = domains[b],
                              quantity = currentState.densities,
                              which = 'both',
                              mapping = 'L2',
                              cmap = 'viridis',
                              visualizeBoth=True,
                              kernel = kernelNameToKernel(configs[b]['kernel']),
                              plotDomain = True,
                              gridVisualization=False, markerSize=2,
                              batch = b, streamLines = False)
    axes[b].set_title(f'Batch {b} {nextData[b]} - t={currentState.time[b]:.2f}s,')
    plots.append(plot)

fig.tight_layout()
```

_diffSPH_ contains more examples on how to then use this data for training with both CConv networks and GNNs.

# Dataset Overview

## Compressible SPH

All simulations have 12 initial conditions available to them. For region cases the density and pressure are randomized per region, for the other cases there is a uniform octave noise across the domain to sample the density and pressure field, and the velocity field as divergence free

##  Circular Regions

Initial | Final
---|---
![](images/compressible/circularRegion/initialConditions/circleCase_16384_145652384_2025-08-13_16-08-23_3_initial.png)|![](images/compressible/circularRegion/finalStates/circleCase_16384_145652384_2025-08-13_16-08-23_3_final.png)
![](images/compressible/circularRegion/initialConditions/circleCase_16384_227846137_2025-08-13_16-52-09_7_initial.png)|![](images/compressible/circularRegion/finalStates/circleCase_16384_227846137_2025-08-13_16-52-09_7_final.png)


## Dual Regions

Initial | Final
---|---
![](images/compressible/dualRegion/initialConditions/dualRegions_16384_145652384_2025-08-13_16-08-31_5_initial.png)|![](images/compressible/dualRegion/finalStates/dualRegions_16384_145652384_2025-08-13_16-08-31_5_final.png)
![](images/compressible/dualRegion/initialConditions/dualRegions_16384_636554131_2025-08-13_16-07-10_1_initial.png)|![](images/compressible/dualRegion/finalStates/dualRegions_16384_636554131_2025-08-13_16-07-10_1_final.png)

## Quad Regions

Initial | Final
---|---
![](images/compressible/quadRegion/initialConditions/quadRegions_16384_227846137_2025-08-13_17-01-57_1_initial.png)|![](images/compressible/quadRegion/finalStates/quadRegions_16384_227846137_2025-08-13_17-01-57_1_final.png)
![](images/compressible/quadRegion/initialConditions/quadRegions_16384_646047911_2025-08-13_16-37-23_3_initial.png)|![](images/compressible/quadRegion/finalStates/quadRegions_16384_646047911_2025-08-13_16-37-23_3_final.png)

## Density Pressure Noise

Initial | Final
---|---
![](images/compressible/pressureDensity/initialConditions/densityPressureNoise_16384_4235_2025-08-13_15-40-20_3_initial.png)|![](images/compressible/pressureDensity/finalStates/densityPressureNoise_16384_4235_2025-08-13_15-40-20_3_final.png)
![](images/compressible/pressureDensity/initialConditions/densityPressureNoise_16384_4235_2025-08-13_15-53-34_2_initial.png)|![](images/compressible/pressureDensity/finalStates/densityPressureNoise_16384_4235_2025-08-13_15-53-34_2_final.png)

## Random Velocity Field

Initial | Final
---|---
![](images/compressible/velocity/initialConditions/velocityNoise_16384_1350991724_2025-08-13_16-51-14_6_initial.png)|![](images/compressible/velocity/finalStates/velocityNoise_16384_1350991724_2025-08-13_16-51-14_6_final.png)
![](images/compressible/velocity/initialConditions/velocityNoise_16384_145652384_2025-08-13_16-19-44_7_initial.png)|![](images/compressible/velocity/finalStates/velocityNoise_16384_145652384_2025-08-13_16-19-44_7_final.png)

## Weakly Compressible SPH

Each simulaiton has 16 initial conditions available, except for the Taylor Green Vortex like initial conditions which are initialized for 2 and 4 vortices only.

### Periodic Domains

BC | Initial | Final
---|---|---
NoSlip   | ![](images/weaklyCompressibleNoSlip/noBoundary/initialConditions/wcsph_False_False_0_16384_2025-08-14_13-17-56_1564495896_initial.png) | ![](images/weaklyCompressibleNoSlip/noBoundary/finalStates/wcsph_False_False_0_16384_2025-08-14_13-17-56_1564495896_final.png)
FreeSlip | ![](images/weaklyCompressibleFreeSlip/noBoundary/initialConditions/wcsph_False_False_0_16384_2025-08-13_14-13-50_1564495896_initial.png) | ![](images/weaklyCompressibleFreeSlip/noBoundary/finalStates/wcsph_False_False_0_16384_2025-08-13_14-13-50_1564495896_final.png)

### With an Obstacle

BC | Initial | Final
---|---|---
NoSlip   | ![](images/weaklyCompressibleNoSlip/obstacle/initialConditions/wcsph_False_True_0_16384_2025-08-14_13-17-56_1564495896_initial.png) | ![](images/weaklyCompressibleNoSlip/obstacle/finalStates/wcsph_False_True_0_16384_2025-08-14_13-17-56_1564495896_final.png)
FreeSlip | ![](images/weaklyCompressibleFreeSlip/obstacle/initialConditions/wcsph_False_True_0_16384_2025-08-13_14-13-50_1564495896_initial.png) | ![](images/weaklyCompressibleFreeSlip/obstacle/finalStates/wcsph_False_True_0_16384_2025-08-13_14-13-50_1564495896_final.png)

### Bounded Domain

BC | Initial | Final
---|---|---
NoSlip   | ![](images/weaklyCompressibleNoSlip/domain/initialConditions/wcsph_True_False_0_16384_2025-08-14_13-17-56_1564495896_initial.png) | ![](images/weaklyCompressibleNoSlip/domain/finalStates/wcsph_True_False_0_16384_2025-08-14_13-17-56_1564495896_final.png)
FreeSlip | ![](images/weaklyCompressibleFreeSlip/domain/initialConditions/wcsph_True_False_0_16384_2025-08-13_14-13-50_1564495896_initial.png) | ![](images/weaklyCompressibleFreeSlip/domain/finalStates/wcsph_True_False_0_16384_2025-08-13_14-13-50_1564495896_final.png)

### Both

BC | Initial | Final
---|---|---
NoSlip   | ![](images/weaklyCompressibleNoSlip/both/initialConditions/wcsph_True_True_0_16384_2025-08-14_13-17-56_1564495896_initial.png) | ![](images/weaklyCompressibleNoSlip/both/finalStates/wcsph_True_True_0_16384_2025-08-14_13-17-56_1564495896_final.png)
FreeSlip | ![](images/weaklyCompressibleFreeSlip/both/initialConditions/wcsph_True_True_0_16384_2025-08-13_14-13-50_1564495896_initial.png) | ![](images/weaklyCompressibleFreeSlip/both/finalStates/wcsph_True_True_0_16384_2025-08-13_14-13-50_1564495896_final.png)


### Taylor Green Vortex

x | Obstacle ? | Domain ? 
---|---|---
-|![](images/weaklyCompressibleFreeSlip/TGV/finalStates/wcsph_False_False_2_16384_2025-08-14_13-05-01_4235_final.png) | ![](images/weaklyCompressibleFreeSlip/TGV/finalStates/wcsph_True_False_2_16384_2025-08-14_13-05-01_4235_final.png)
-|![](images/weaklyCompressibleFreeSlip/TGV/finalStates/wcsph_False_True_2_16384_2025-08-14_13-05-01_4235_final.png)|![](images/weaklyCompressibleFreeSlip/TGV/finalStates/wcsph_True_True_2_16384_2025-08-14_13-05-01_4235_final.png)