# Foiling vortex traps around buildings

I have had three houses with right angles in the layout, and in each one that configuration causes vortices to form that suck in leaves, snow, and any debris blowing by and keep it in the nook of the building. Rough idea in the following sketch, with the prevailing wind from the left:

What passive methods or designs can be used to disrupt and prevent such vortices?

• You could plant trees or look at bridge design. They have issues with vortices causing resonance and means to alleviate the vortices or prevent them from forming. The configuration and the wind direction is as indicated in the picture? I can only see two buildings. How tall are the buildings relative to each other? Feb 15 '15 at 20:33
• Drawing is actually a single building. In every case I've seen this the building height is a uniform 1 or 2 stories, but the roof lines have varied, so the criteria for vortex formation appear to be rather flexible! Note also: in two of the houses the prevailing wind came through a mature tree line within 25 yards of the building. Feb 15 '15 at 20:52

CFD

I ran this situation through a couple of simple 2D CFD models. As you can see from the pictures below, one way to keep debris from gathering in this area is to increase the velocity of wind in the corner. To do this, you need to place an obstacle that will direct the wind into the corner.

Original Situation:

Even with this, there will be a dead spot in the corner. This should help to lessen it though.

Another benefit of this configuration is that it works just the same if the wind is coming form the top.

What kind of obstacle?

The exact design of the obstacle wouldn't need to be too involved. A planter or solid bench may be enough to make a difference. The main criteria are:

1. Solid so that the wind is directed around it.
2. High enough that the wind moving over top of it doesn't affect the wind moving around.

There will likely be some trial and error.

Build a fence or plant a hedge line to block off the right angle (connecting the two corners of the triangle that rubbish tends to collect in). That way the wind, and the stuff it's carrying, should mostly slide around the structure.