CFL 条件

判断显式时间推进中当前时间步是否稳定。

visual calculator数值与稳定性

先看流动形态，再相信数字。

该工具把 CFD 设置转换为工况、尺度和主导效应提示。调节下方计算器，观察动态图与计算结果如何一起变化。

输入尺度

模型

判断

CFLnumericsstability

公式

KaTeX rendered

\begin{aligned}\text{C = u dt / dx}\end{aligned}

ASCII source

C = u dt / dx

u — wave speed (m/s)Δt — time step (s)Δx — grid spacing (m)C_max (e.g., 1.0 advect, 0.5 RK4)

C (current)

0.1000 ✓ stable

Δt_max for current Δx

5.000e-3 s

Explicit Euler 1-D advection: C_max = 1. Higher-order RK (e.g., RK4) typically allows C ≈ 1.4–2 for advection, but viscous & non-linear terms add tighter limits.

CFL numerics stability