Which exhaust do you take?

[raymondu999]

Why would you want to increase the size of the exhaust channel? Coanda works fine on a ramp too.

I think in fact doing the opposite, making the tunnel smaller, could be beneficial. Certainly there was a trend that they were in fact shrinking the tunnel as the year went on. They had the first big one in Valencia, then proceeded to shrink it more and more in the last third of the season. I can only surmise that the net result of such a system (with a smaller sidepod tunnel) was a net gain.

[allstaruk08]

why are you asking me a questions when i asked why it wouldnt work :S lol

i thought that if the tunnel goes all the way to the side of the diffuser the flow will be directed more concentrated in that area

[Spacepace]

Mclaren's solution is inferior.

To the final iteration of the redbull's. The redbull concept was the better one from the start, but it took a while to refine.
It should be observed that the rb8 has separated the two systems definitely, and there is nothing to will cause any mixing due to there being a rigid barrier between the flow over the top and the flow going towards the middle of the car.

The redbull exhuast flow direction is also less dependent on outside factors like the free stream speed. Secondly the exhaust flow direction has less changes than the mclaren. In fact it basically straight shot.
The mclaren has more direction changes ( free stream dependent as well) as the flow comes out the pipes, curves down on the flow then crawls allong it to the edge of the duffuser. The rb8 flow is chuted right where it needs to be, more direct and maybe with less eddies.
It cannot be said that the mclaren solutions has less drag either, we cannot know that for certain.

Interesting. Can I get you to expand on the point you made about the exhaust being effected by the free stream speed and the Red Bull exhaust being chuted right where it needs to be. Are you implying that the exhaust on the RB8 actually will curve down and land inbetween the diffuser and tyre?

[raymondu999]

Are you implying that the exhaust on the RB8 actually will curve down and land inbetween the diffuser and tyre?

Yes. By virtue of the Coanda effect, the exhaust gases will get sucked to the ramp bodywork and follow along its path to the diffuser.

[Spacepace]

Are you implying that the exhaust on the RB8 actually will curve down and land inbetween the diffuser and tyre?

Yes. By virtue of the Coanda effect, the exhaust gases will get sucked to the ramp bodywork and follow along its path to the diffuser.

I was actually looking for an answer from ringo. And if what he was implying was the Red Bull's exhaust act more like an arc instead of following the shape of the bodywork and hitting the floor.

[wesley123]

under low speed the exhaust has the chance of blowing upwards, because that is the way the exhausts are aimed and have to be aimed to conform to the rules. This is indifferent to both solutions, although stronger downwash will help.

The coanda exhaust works by pushing the exhaust plume down by using regular air, nothing more or less.

[raymondu999]

There s also low pressure below it, by virtue of Coanda.

[Spacepace]

under low speed the exhaust has the chance of blowing upwards, because that is the way the exhausts are aimed and have to be aimed to conform to the rules. This is indifferent to both solutions, although stronger downwash will help.

The coanda exhaust works by pushing the exhaust plume down by using regular air, nothing more or less.

I always thought the coanda was the effect of the air wanting to attach to a surface so once it exits the trough it will suck down to the floor because there is no air there(low pressure). With the airflow coming from the front lower half of the sidepods going under the exhaust bulge/tunnel there is not much air below the exit of the trough/ramp so the exhaust and down wash will find the easiest way to go which is down below. My thing with McLaren being superior is that there is a bigger volume of air coming down on the McLaren exhaust then the Red Bull. I was reading a techincal analysis of someone's exhaust in autosport by Gary Anderson. And what he was saying was that if you took a garden hose and put it in a stream of water pointing at an angle the deeper you put it in the stream the greater the stream would bend that water coming from the hose and merg with the streams flow. This is what I am getting at with the McLaren, it has one to two inches from the top of the exhaust exit to the start of the exhaust trough where the downwash comes down. They get more downwash on that exhaust then the RB8 which has its exhaust at the top of the stream so to speak.

[raymondu999]

Kitchen torch, cocktail shaker, 0 kph:

[Spacepace]

Very cool

[Absolutelee]

Kitchen torch, cocktail shaker, 0 kph:

really good illustration of coanda there!

[raymondu999]

As demonstrated in Pup's experiment - Coanda is not about external air above the exhaust flow (exhaust flow demonstrated by the flame) pushing the path of the gas stream down. It's about the curvature of the surface actually sucking down on the gas.

[Spacepace]

As demonstrated in Pup's experiment - Coanda is not about external air above the exhaust flow (exhaust flow demonstrated by the flame) pushing the path of the gas stream down. It's about the curvature of the surface actually sucking down on the gas.

Yeah isn't that the exhaust wants to attach to a surface

[wesley123]

Is there really a surface to attach to? Well you have the small tunnel in which the exhaust exits, but from out there, there is nothing the exhaust can attach to to use the shown effect

[beelsebob]

Is there really a surface to attach to? Well you have the small tunnel in which the exhaust exits, but from out there, there is nothing the exhaust can attach to to use the shown effect

The tunnel is all that's needed – look at the picture above – notice how the "exhaust" continues to flow downwards off the shaker – the tunnel changes the direction of flow.