We investigate two important, common fluid flow patterns from computational fluid dynamics (CFD) simulations, namely, swirl and tumble motion typical of automotive engines. We study and visualize swirl and tumble flow using three different flow visualization techniques: direct, geometric, and texture-based. When illustrating these methods side-by-side, we describe the relative strengths and weaknesses of each approach within a specific spatial dimension and across multiple spatial dimensions typical of an engineer's analysis. Based on this investigation we offer perspectives on where and when these techniques are best applied in order to visualize the behavior of swirl and tumble motion.

Visualization of swirl motion using texture-based flow visualization on a slice (200 frames).

Visualization of swirl motion using dye injection: interactive, animated streamlines (400 frames).

Since 2D streamlines on slices may be considered misleading, here we use 3D streamlets to visualize the normal component of the flow through the slice (240 frames).

Animated, texture-based flow visualization used to visualize tumble flow on a slice (200 frames).

Tumble motion visualized using dye injection on a 2D slice. Note the saddle point highlighted by the orange, brown and green dye sources (350 frames).

Tumble motion visualized at the surface with an animated texture-based approach. Note that the amount of smearing in the texture can encode velocity magnitude (150 frames).

Swirl flow at the surface visualized with streamlines computed with a traditional particle tracing approach (100 frames).

Visualizing swirl flow at the surface with an animated texture-based approach (270 frames). Click here for a similar result with a velocity clamp applied (270 frames).

Dye injection is used to highlight a separatrix between two critical points on the surface of the in-cylinder flow (200 frames).

Timelines are used to highlight the divergent and convergent properties of the tumble flow at the surface (200 frames).

Color-mapped, animated streamlines are used to visualize swirl motion in 3D (300 frames).

A hybrid approach of (1) a velocity isosurface of 5.0 m/s, (2) 3D streamlines and (3) texture-based flow visualization on the isosurface is used to visualize swirl motion (270 frames).

Animated, color-mapped streamlines seeded with two seeding planes used to visualize 3D tumble flow (270 frames).

A hybrid approach of (1) a pressure isosurface of 90,000 pascals, (2) animated streamlines, and (3) texture-based flow visualization on a slice is used to visualize tumble motion in 3D (270 frames).