# iTurbo

> Direct Numerical Simulation of 2D incompressible homogeneous turbulence. (iPhone/iPad app by Torbjorn Sjogren.)

- Source: https://appshunter.io/ios/app/iturbo/id314368331 (this page in markdown: same URL + `.md`)
- Developer: [Torbjorn Sjogren](https://appshunter.io/developer/313743954)
- Category: Education
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 18.0 · 2 MB
- Languages: English
- Released: 2009-05-06
- Data updated: 2026-06-24
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/iturbo/id314368331/reviews.md

## What is iTurbo?

This application performs a Direct Numerical Simulation (DNS) where the Navier-Stokes equations are solved for two dimensional incompressible homogeneous turbulence. These equations are a set of nonlinear partial differential equations. The time stepping is performed with a simple Euler method where the time step is calculated so that the CFL number does not exceeds the given number (should be less than 0.8 otherwise the simulation blows up). The equations are solved in the Fourier space where the calculation of the nonlinear term transforms to a simple multiplication. The main CPU usage is consumed by transforming the vorticity field back and fourth between the Normal space where the time-stepping is performed and the Fourier space where the nonlinear term is calculated.

## Key features

- Direct Numerical Simulation (DNS)
- Navier-Stokes equation solver
- 2D incompressible turbulence
- Euler time stepping
- Fourier space calculations
- Vorticity field transformation


## Frequently asked questions about iTurbo

### What is iTurbo used for?

iTurbo performs a Direct Numerical Simulation (DNS) to solve the Navier-Stokes equations for two-dimensional incompressible homogeneous turbulence. It's designed for simulating complex fluid dynamics scenarios.

### How does iTurbo simulate turbulence?

It solves the Navier-Stokes equations using a simple Euler method for time stepping and performs calculations in Fourier space for efficiency. The simulation involves transforming the vorticity field between normal and Fourier spaces.

### What is the CFL number requirement for iTurbo?

The time step in iTurbo is calculated to ensure the CFL number does not exceed a given value. If the CFL number is greater than 0.8, the simulation will likely fail.

### What devices does iTurbo support?

iTurbo is available on iPhone and iPod devices. It is designed for iOS platforms.

### What is the age rating for iTurbo?

iTurbo has an age rating of 4+, making it suitable for a wide range of users interested in scientific simulations.

### How often is iTurbo updated?

The latest version of iTurbo is 1.3, which was last updated on May 19, 2026. This indicates a recent update for the application.

### Does iTurbo have ads?

No, iTurbo does not contain advertisements. The application is free to use without any ad interruptions.

### What is the user rating for iTurbo?

iTurbo has a perfect rating of 5.0 stars based on one review. This suggests a highly positive user experience from its current users.

## Version history (last 4 releases)

### 1.3 — 2026-05-19

• Simulation now fills the screen on all iPhone sizes
• Default resolution doubled (N=384) with a new N=768 option for finer detail
• Higher default Reynolds number (Re=10000) for richer turbulence

### 1.2 — 2016-05-17

This app has been updated by Apple to display the Apple Watch app icon.

Updated for iOS 7 and above

### 1.1 — 2011-12-22

Optimized simulation code
Higher simulation resolution

### 1.0 — 2009-05-06

No release notes.

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## More apps by Torbjorn Sjogren

- [ATimer](https://appshunter.io/ios/app/atimer/id333262096)
- [Kutta Joukowski](https://appshunter.io/ios/app/kutta-joukowski/id370836602)
- [Double Pendulum Simulation](https://appshunter.io/ios/app/double-pendulum-simulation/id370962405)
- [Triple Pendulum](https://appshunter.io/ios/app/triple-pendulum/id371860711)
- [Mechanical Pendulums](https://appshunter.io/ios/app/mechanical-pendulums/id377376047)

All apps by Torbjorn Sjogren: https://appshunter.io/developer/313743954

## Related topics

[iturbo](https://appshunter.io/ios/topics/iturbo)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-24.*