Cylinder

Wake dynamics behind a stationary circular cylinder measured with time-resolved PIV, paired with matched CFD simulations.

Visualizations

Real-world
Simulated

Key stats

Item Value
n_traj 92 × 2 (paired real + numerical)
n_frame 3990
\(\Delta t\) \(2.5\times 10^{-3}\) s
Resolution (real) 128×256
Resolution (sim) 64×128
Modalities (real) \(u,v\)
Modalities (sim) \(u,v,p\)
Memory 190.50 GB

Note

We use n_traj = X × 2 to indicate paired trajectories: X real-world and X numerical trajectories for the same scenario.

Physical parameters

  • Reynolds number: 1800–12000
  • Geometry: cylinder diameter \(D=30\) mm
  • Sampling: 400 Hz for 20 s; after preprocessing the sequence length is n_frame = 3990

HF Datasets format

This scenario is distributed as Hugging Face Datasets (Arrow) under cylinder/hf_dataset/.

Splits

  • real_{train|val|test}
  • numerical_{train|val|test}

Schema (high level)

  • sim_id (string): trajectory identifier
  • time_id (int): window start index
  • u (bytes), v (bytes): float32 arrays encoded as bytes
  • p (bytes; numerical only): pressure channel
  • shape_t, shape_h, shape_w (int): shape metadata for decoding

Eval splits & subsets

We provide two layers of splitting:

  • Dataset split (train/val/test): the standard split in hf_dataset/*_{train|val|test}.
  • Eval subset (test_mode): an optional filter inside val/test to select trajectories by parameter regime.

The subset membership is defined by JSON mapping files (downloaded as "metadata"):

  • cylinder/in_dist_test_params_real.json
  • cylinder/out_dist_test_params_real.json
  • cylinder/remain_params_real.json
  • cylinder/in_dist_test_params_numerical.json
  • cylinder/out_dist_test_params_numerical.json
  • cylinder/remain_params_numerical.json

How to interpret these files and test_mode:

  • in_dist: in-distribution parameter settings (held out for evaluation).
  • out_dist: out-of-distribution / boundary parameter settings (OOD generalization).
  • seen: parameter settings used for training (defined by remain_params_*).
  • unseen: parameter settings not used for training (union of in_dist + out_dist).

Download

See Getting Started for full setup. Quick commands:

# Evaluation metadata (small; includes the JSON mapping files)
realpdebench download --dataset-root <DATASET_ROOT> --scenario cylinder --what metadata

# HF dataset shards (large)
realpdebench download --dataset-root <DATASET_ROOT> --scenario cylinder --what hf_dataset