Fluid Flow Streamline Simulator
Visualize 2D incompressible potential flow past obstacles. Combine uniform free-stream, sources, sinks, and circulation. Watch animated tracer particles, streamlines, and a velocity-magnitude colormap update as you adjust the geometry.
Click an obstacle to select it. Particles drift with the velocity field; streamlines (white/blue lines) are integral curves of the steady flow. Speed colormap shows velocity magnitude.
Controls
Free-Stream Flow
Obstacles
Display
Presets
Reference Guide
Stream Function & Streamlines
In 2D incompressible flow, the velocity components are derivatives of a scalar stream function ψ.
Lines of constant ψ are streamlines. No fluid crosses them since velocity is tangent.
Flow Past a Cylinder
The doublet representation of flow past a cylinder of radius R in uniform stream U gives:
Velocity at the top is exactly 2U. Surface stagnation points appear at the leading and trailing edges (±R, 0).
Kutta-Joukowski (Lift)
An obstacle with circulation Γ in a uniform stream U experiences a lift force per unit span:
This is the foundation of airfoil theory. Try the rotating-cylinder and airfoil presets to see lifting flows.
Bernoulli's Principle
Along a streamline, energy conservation gives a relation between pressure and speed:
Where speed increases (red on the colormap), pressure decreases. This explains lift, the Venturi effect, and curved-ball trajectories.
