FluidPeek Learn

Learn flow by testing shapes.

2D CFD mini game

Cd, Cl, and L/D

Use drag, lift, and lift-to-drag ratio to compare shapes. Draw a 2D body below and run a lightweight CFD test.

CdDrag coefficient. Lower usually means less resistance.

Cl ↑Lift coefficient. Upward force is positive.

L/DLift divided by drag. Higher is better for wing-like shapes.

2D CFD mini game

Shape the flow.

Draw one closed body. Keep enough area, spend limited ink, then compare Cd, Cl, and L/D.

Draw a closed body. Low Cd or high L/D wins.

Ink

Stroke budget 100%

Result

Area target--

Cd--

Cl ↑--

L/D--

StatusDraw

Ranking

--Loading--

What does CFD calculate?

CFD breaks a flow field into cells, solves velocity and pressure in each cell, then turns those numbers into visible flow patterns.

Wakes, separation, and vortices

Separated flow creates slow wakes and swirling structures. These patterns explain why blunt shapes usually have high drag.

Planned

Pressure, velocity, and surface flow

Pressure and velocity contours show where a shape accelerates flow, creates suction, or produces force.

Everyday Flow 01

Why does a flag flutter?

A flag moves because the wind around it keeps separating, swirling, and changing pressure. CFD turns that invisible motion into visible patterns.

1Wind meets fabric

2Pressure changes

3Vortices shed

01 / WIND

The wind cannot pass through the flag.

Air has to split, turn, and speed up around the fabric. That creates uneven pressure on the two sides.

02 / PRESSURE

The force keeps switching sides.

When one side has lower pressure, the flag is pulled that way. A moment later, the flow changes and the pull can reverse.

UpUp pUpU UpUp

03 / VORTICES

Small swirls leave the trailing edge.

These alternating vortices are why the motion feels rhythmic instead of random.

04 / CFD VIEW

The invisible flow becomes readable.

Velocity colors, pressure maps, particles, and streamlines help show where the air speeds up, slows down, and starts to swirl.

Velocity

Pressure

Forces

FluidPeek

Distributed CFD

Sign in

Signed in

Bring in the shape.

Discretize the space.

Solve each cell.

Watch the flow.

Read the field.

Keep the result.

CFD Source Search