fluidsim

fluidsim is a skill for Claude Code, Codex from silverstein/claude-scientific-skills-desktop. It costs 69 tokens per session (2,504 once invoked), scanned A, a copy of fluidsim, MIT.

A Python framework for computational fluid dynamics, the computer simulation of moving fluids such as air and water. It includes solvers for several fluid-flow equations and tools for analyzing results.

In plain words
What is it for?
It helps run two- or three-dimensional Navier–Stokes simulations, shallow-water and stratified-flow models, turbulence and vortex studies, parallel computations, and visual analysis of outputs.
Why use it?
It removes the need to build common simulation, execution, and analysis infrastructure from scratch when studying fluid motion.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps run two- or three-dimensional Navier–Stokes simulations, shallow-water and stratified-flow models, turbulence and vortex studies, parallel computations, and visual analysis of outputs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/silverstein/claude-scientific-skills-desktop/fluidsim
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add silverstein/claude-scientific-skills-desktop --skill fluidsim
Clone the repo
git clone --depth 1 https://github.com/silverstein/claude-scientific-skills-desktop

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for fluidsim

README.md
[![agentmods](https://agentmods.dev/badge/skills/silverstein/claude-scientific-skills-desktop/fluidsim/github.svg)](https://agentmods.dev/skills/silverstein/claude-scientific-skills-desktop/fluidsim)
Your own site
<a href="https://agentmods.dev/skills/silverstein/claude-scientific-skills-desktop/fluidsim"><img src="https://agentmods.dev/badge/skills/silverstein/claude-scientific-skills-desktop/fluidsim/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fluidsim

Your own site · 80×15
<a href="https://agentmods.dev/skills/silverstein/claude-scientific-skills-desktop/fluidsim"><img src="https://agentmods.dev/badge/skills/silverstein/claude-scientific-skills-desktop/fluidsim.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,504 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 92% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00069 $0.02504
Opus 5 $0.00034 $0.01252
Sonnet 5 $0.00014 $0.00501
Haiku 4.5 $0.00007 $0.00250

Measured 11d ago against content hash 4673558954e6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

fluidsim scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

92% identical to fluidsim — 7 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

corpus/fluidsim/SKILL.md · 344 lines

How it starts

The opening of the file, as written. The whole thing — 344 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FluidSim

Overview

FluidSim is an object-oriented Python framework for high-performance computational fluid dynamics (CFD) simulations. It provides solvers for periodic-domain equations using pseudospectral methods with FFT, delivering performance comparable to Fortran/C++ while maintaining Python's ease of use.

Key strengths:

  • Multiple solvers: 2D/3D Navier-Stokes, shallow water, stratified flows
  • High performance: Pythran/Transonic compilation, MPI parallelization
  • Complete workflow: Parameter configuration, simulation execution, output analysis
  • Interactive analysis: Python-based post-processing and visualization

Core Capabilities

1. Installation and Setup

Install fluidsim using uv with appropriate feature flags:

# Basic installation
uv uv pip install fluidsim

# With FFT support (required for most solvers)
uv uv pip install "fluidsim[fft]"

# With MPI for parallel computing
uv uv pip install "fluidsim[fft,mpi]"

Set environment variables for output directories (optional):

export FLUIDSIM_PATH=/path/to/simulation/outputs
export FLUIDDYN_PATH_SCRATCH=/path/to/working/directory

No API keys or authentication required.

See references/installation.md for complete installation instructions and environment configuration.

2. Running Simulations

Standard workflow consists of five steps:

Step 1: Import solver

from fluidsim.solvers.ns2d.solver import Simul

Step 2: Create and configure parameters

params = Simul.create_default_params()
params.oper.nx = params.oper.ny = 256
params.oper.Lx = params.oper.Ly = 2 * 3.14159
params.nu_2 = 1e-3
params.time_stepping.t_end = 10.0
params.init_fields.type = "noise"

Step 3: Instantiate simulation

sim = Simul(params)

Step 4: Execute

sim.time_stepping.start()

Step 5: Analyze results

sim.output.phys_fields.plot("vorticity")
sim.output.spatial_means.plot()

See references/simulation_workflow.md for complete examples, restarting simulations, and cluster deployment.

Read the full file on GitHub · 344 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 344 lines · 69 tokens per session scan A 4673558954e6

Subscribe to this mod's changes

fluidsim is a skill published in the GitHub repository silverstein/claude-scientific-skills-desktop (22 stars, last pushed 5mo ago), licensed MIT. It adds 69 tokens to every session and 2,504 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 92% identical to fluidsim, differing in 7 lines, and is treated as a copy.

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