iTurbo vs x
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
iTurbo
This app simulates fluid dynamics by solving Navier-Stokes equations for 2D incompressible turbulence. It uses a direct numerical simulation method with Euler time stepping and Fourier space calculations for efficiency.
- Direct Numerical Simulation (DNS)
- Navier-Stokes equation solver
- 2D incompressible turbulence
- Euler time stepping
- Fourier space calculations
- Vorticity field transformation
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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.
x
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x-Cal is an ergonomic scientific calculator, in both portrait and landscape orientations, using RPN (c) Great for professional and educational use, it allows to quickly develop an understanding of register operations and basic programming Features fixed, scientific or engineer number formats, trigonometric and hyperbolic calculations in radians, degrees or grades, basic statistical computations, linear correlations, combinations, etc. Swipe on the top result display area to view the arithmetic register stack, tap on the top to display other registers such as storage register, statistical registers and program steps Record programs such as a quadratic equation solver, or display graphs to visualize functions y = f(x) At any time look, copy and paste text style computations into e-Mails, notes, etc.
Screenshots
Verdict
The clearest difference is update cadence: x at fortnightly against iTurbo's every 54 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
iTurbo ships an update every 54 months, x fortnightly. The most recent releases landed on September 29, 2026 and September 28, 2026 respectively.
| Parameter | iTurbo | x |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 54 months | Fortnightly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPod — better | iPhone |
| Requires iOS | 18.0 | 18.0 |
| Further details — not scored | ||
| Size | 2 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | ManneTroll Solutions | FMILLET |
In-app purchases
iTurbo
No in-app purchases
x
No in-app purchases









