Design

FIrst Look – Autodesk ForceEffect Flow

If you thought CFD was too difficult, too expensive and needed a supercomputer, you have not been listening. For a couple of years now, flow analysis has been available on an iPad. For free. Granted, it is not a full CFD program — but it can still be a lot of fun.

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Streamlines developing around simulation Editor Shawn Wasserman crouching silhouette drawn automatically by ForceEffect Flow, which helped to achieve a dramatic drop in his coefficient of drag on the slopes in this episode of “Some Assembly Required”

Autodesk ForceEffect Flow lets you visualize 2D fluid
flow around an object. Any object. An object that you might photograph or
sketch. You can even create a profile as a freehand sketch. See
streamlines around your automobile silhouette, air foil sections, a Tour de
France time trial bike rider, or what have you. It’s so easy you will think it’s
a game. You will wonder if it is a real CFD program. Real CFD programs (Fluent, CD-adapco,
COMSOL, etc.) are tens of thousands of dollars, right? And don’t you
need a PhD to even get a crack at using them? 

We’ve been hearing claims of greater ease of use from makers of “real CFD” programs. For them, Autodesk sets a new standard.  Slider bars adjust the speed of the test object in relation to the wind. The
streamlines adjust accordingly. The invisible world of fluid flow is now visible
— to all! No PhD required. We were able to see smoke trails around an object (our editor) whose shape was captured by the camera in the tablet. 

Rest assured, the code behind Autodesk ForceEffect Flow is the real thing.

The solver being used under the hood is the same one that was used for CFdesign,
a general purpose CFD program, now part of the Autodesk simulation portfolio
(Autodesk bought Blue Ridge Numerics, makers of CFdesign in 2011).

If you have been doing back of the envelope calculations, this is way better. Don’t confuse it with full fledged CFD program. Again, it is limited to 2D, a simplified wind tunnel. Airspeed is
limited to 160 mph (260 kph). Drag force is calculated based on the shape being
constant along the depth axis, which may never be the case, but still, it could
be useful for comparison of one shape to another. Of course, being 2D precludes
generating a control volume. In fact, there is no mention of a mesh whatsoever.
I know, the real world flow is really a 3D problem. The streamlines around a car
travelling at speed do not stay in plane — except along the vertical plane of
symmetry. . . . But really, are you going to complain when being handed an
application that will amaze everyone you show (who is not a fellow egghead)?
Prepare to show family what the air is doing around the family van. Show friends
the best tuck position to maintain as they ski down the slopes. Who knows, they
might even think engineering is cool. And maybe even you.

Pricing and Availability

The Autodesk ForceEffect Flow app is free from the iTunes App Store for
iPhone, iPad and iPod Touch.

See Also