# Viv Analysis Strouhal Number

> Sub-skill of viv-analysis: Strouhal Number (+2).

- Skill: `vamseeachanta/viv-analysis-strouhal-number` (Agent Skill)
- Install (CLI): `npx skillmds@latest add vamseeachanta/viv-analysis-strouhal-number`
- Raw SKILL.md: https://api.skillmd.com/api/skills/vamseeachanta/viv-analysis-strouhal-number/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: vamseeachanta (https://skillmd.com/u/vamseeachanta)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/vamseeachanta/viv-analysis-strouhal-number

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# Strouhal Number (+2)

## Strouhal Number


| Geometry | Strouhal Number |
|----------|-----------------|
| Smooth cylinder | 0.2 |
| Rough cylinder | 0.21 |
| Straked cylinder | 0.14-0.18 |

## Reduced Velocity Ranges


| Condition | Reduced Velocity Range |
|-----------|----------------------|
| Cross-flow VIV onset | 4 - 8 |
| In-line VIV onset | 1 - 3.5 |
| Lock-in region | 5 - 7 |

## Added Mass Coefficients


| Configuration | Ca |
|---------------|-----|
| Circular cylinder in infinite fluid | 1.0 |
| Near seabed (gap/D = 0.5) | 1.2 |
| Near seabed (gap/D = 0.1) | 2.0 |