piv_swirling_strength — PIV field op

• Data kinds: flow2d → image2d

• Call: import pivops; pivops.piv_swirling_strength(flow, spacing=1.0) (or opspiv.get("piv_swirling_strength"))

Usage

> This operator's description has not been translated yet. The original text follows as it is.

渦回転強度 λ_ci —— 速度勾配テンソルの複素固有値の虚部の大きさ。

Q 基準と同じく「せん断と渦を区別する」量だが、こちらは**回転の角速度に

等しい単位**を持つ(1/フレーム)。実測: 剛体回転 ω=0.01 で `0.01`、

一様膨張とせん断で `0.0`。

固有値が実数(= 回転していない)の場所は 0 を返す。各点で独立な 2x2 の

固有値なので、格子全体をベクトル化して一度に解いている。

Detailed usage guide

• piv_displacement family guide

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• (none yet)

Ops the type connects to (they accept image2d as input)

piv_cross_correlate · piv_multipass · piv_deform_pass · strain_from_displacement · correlation_quality · speckle_quality

Same category (field)

piv_vorticity · piv_divergence · piv_flow_magnitude · piv_to_velocity · piv_velocity_gradient · piv_q_criterion · piv_strain_rate

*Provenance: pivops.py — PIV operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.