The latest annoying trend: notched spoilers

[Dakar Timm]

Notched spoilers have been observed to be more effective than uniform spoilers to suppress the flow-induced cavity resonance of vehicles with open sunroofs. In this study, a few mechanisms possibly involved in buffeting suppression from notched spoilers were investigated experimentally and numerically. One objective was to investigate the spatial coherence and phase of the wall pressure fluctuations downstream of notched spoilers in comparison with the same quantities for uniform spoilers. Another objective was to gather detailed measured data to allow the verification of computer simulations of the flow over the notched spoiler. Experiments were performed to measure the velocity and wall pressure fields downstream of spoilers mounted on the rigid floor of a closed test section wind tunnel for different spoiler heights. Efforts were made to reproduce the spoiler and wind tunnel geometry and boundary conditions of the experimental set-up in the numerical simulations. The numerical investigation used the Lattice Boltzmann Method (LBM), with the so-called Very Large Eddy Simulation (VLES) viscosity turbulence model. The results of the numerical investigation were in satisfactory agreement with measured data at low frequencies, where buffeting is expected to occur. The results clearly showed that the notches act as streamwise vortex generators. They reduced spoiler drag, resulting in an upstream shift of the flow reattachment region. The results confirmed that the streamwise vortices break down the homogeneity of the leading edge cross-stream vortices predominantly responsible for the cavity excitation. This decreased the cross-stream coherence of the surface pressure field, thereby reducing the magnitude of the net equivalent excitation force acting over the surface downstream.
Simplified , the notch allows the passing air to realign itself sooner and smoother . This helps in fuel mileage .
Years back , bungee webs ,were all the rage with pickup truck people .
thousands of folks took off their tailgate and installed huge bungee webs and cargo nets instead of the tailgate.
All sorts of claims were made about improved economy .
Finally some folks put the (sales ) theory to the test . Turns out the trucks with the factory tailgate still installed got significantly better mileage .

 

[AR67GTX]

I like them better without the notch. Probably should have held on to this.

 

[RemCharger]

Notched spoilers have been observed to be more effective than uniform spoilers to suppress the flow-induced cavity resonance of vehicles with open sunroofs. In this study, a few mechanisms possibly involved in buffeting suppression from notched spoilers were investigated experimentally and numerically. One objective was to investigate the spatial coherence and phase of the wall pressure fluctuations downstream of notched spoilers in comparison with the same quantities for uniform spoilers. Another objective was to gather detailed measured data to allow the verification of computer simulations of the flow over the notched spoiler. Experiments were performed to measure the velocity and wall pressure fields downstream of spoilers mounted on the rigid floor of a closed test section wind tunnel for different spoiler heights. Efforts were made to reproduce the spoiler and wind tunnel geometry and boundary conditions of the experimental set-up in the numerical simulations. The numerical investigation used the Lattice Boltzmann Method (LBM), with the so-called Very Large Eddy Simulation (VLES) viscosity turbulence model. The results of the numerical investigation were in satisfactory agreement with measured data at low frequencies, where buffeting is expected to occur. The results clearly showed that the notches act as streamwise vortex generators. They reduced spoiler drag, resulting in an upstream shift of the flow reattachment region. The results confirmed that the streamwise vortices break down the homogeneity of the leading edge cross-stream vortices predominantly responsible for the cavity excitation. This decreased the cross-stream coherence of the surface pressure field, thereby reducing the magnitude of the net equivalent excitation force acting over the surface downstream.

In other words just typical engineering advancements the average layman can't understand.

 

[Dakar Timm]

In other words just typical engineering advancements the average layman can't understand.

If I can understand it , it's not that hard . Air must be split or diverted when it hits the front of the vehicle .
As the air passes the rear of the vehicle ,it must rejoin itself . The notch smooths out the turbulance . The air going around the sides
is going a differant speed and path than the air going over the top . The air coming up from underneath is pressurized to some extent as well . The air coming off the top wants to continue it's path . The air hits the pressurized air from underneath and is pushed up and curls up and back onto itself.
Now ,you have vacuum ,or pressure differance .The notch relieves some of the pressure .
I hope this helps.
https://www.pond5.com/stock-footage...nd-tunnel?dd_referrer=https://www.google.com/

 

[RemCharger]

If I can understand it , it's not that hard . Air must be split or diverted when it hits the front of the vehicle .
As the air passes the rear of the vehicle ,it must rejoin itself . The notch smooths out the turbulance . The air going around the sides
is going a differant speed and path than the air going over the top . The air coming up from underneath is pressurized to some extent as well . The air coming off the top wants to continue it's path . The air hits the pressurized air from underneath and is pushed up and curls up and back onto itself.
Now ,you have vacuum ,or pressure differance .The notch relieves some of the pressure .
I hope this helps

I understand and don't doubt engineering simply because I haven't seen it before. When new cars are going 200mph of course they're going to refine the aerodynamics. That's how these were born. ( know what are they from?)

 

[Dakar Timm]

I understand and don't doubt engineering simply because I haven't seen it before. When new cars are going 200mph of course they're going to refine the aerodynamics. That's how these were born. ( now what are they from?)
View attachment 1845511

I couldn't tell where they came from . I have more than enough stuff in my garage I have no idea where it came from !
EPA mandated fuel mileage is the real answer . It why we have recessed door handles and hidden wiper blades . Engineering has been tasked with minute incremental reductions in drag co efficents. My employer makes the variable displacement oil pumps used on all the Chrysler and Jeep products . Reducing windage in the oil pan is the part of the reason for the oil pump for this solenoid .
I'm not a fan of anything limiting oil getting in the path of valves and pistons . Yet average corporate fuel mileage trumps what we as consumers woulds prefer .

 

[WileE]

Well, 99% street car spoilers do virtually nothing because you have be running triple digits to see any worthwhile or measurable performance gain. No need to be annoyed by a notch that reduces the performance of something that does not perform anyway. Theses spoilers are for aesthetics only.

That is merely cosmetic, will do nothing for that car 99% time it is driven.

Great minds think alike.

View attachment 1845090 From what I understand that at 160MPH the down force is amazing.

More importantly, serves as a nice canopy for shade on a hot, sunny day.

 

[RemCharger]

I couldn't tell where they came from . I have more than enough stuff in my garage I have no idea where it came from !

They are from Nascar development helping the Charger win the cup in 66. Helped it gain about 15- 20 mph I believe. Thus the 67 Charger became the first north American produced car with a spoiler.

 

[69 Sleeper Bee]

I bought my Scat Pack last summer and it has a little notch in the middle of the rear spoiler, which to tell the truth I never have paid a lot of attention to.
What bothers me more are these "stake" rear valence mods all the "cool kids" seem to be adding to their rides these days. I see no usefulness to them besides maybe being able to plow a farm field with your car if you added them in conjunction with jacking up the front in a sort of Carolina Squat mod, which is yet another irritating trend in recent years.
This listing claims the stakes improve downforce and stability, which I find hard to believe but without access to a wind tunnel I can't disprove.

View attachment 1845454

Rear diffusers only work if you have the flat pan underside that directs air to them and creates something to the effect of negative pressure sucking the car to the track. I imagine they are only effective over 100 mph or more.

 

[6PKRTSE]

I hate any kind of spoiler or wing. Except a 70 AAR Cuda / T/A Challenger spoiler or a newer 08-14 Challenger R/T style spoiler. I prefer the look of most plain Jane 4 cyl or 6 cyl models over most blinged out performance model cars these days.

 

[440 4 speed]

I understand and don't doubt engineering simply because I haven't seen it before. When new cars are going 200mph of course they're going to refine the aerodynamics. That's how these were born. ( know what are they from?)
View attachment 1845511

Not too many will, I do.

 

[Richard Cranium]

Who wooden like that in their ride? LOLl

It's gorgeous. It really spruces up the look!

 

[Hey-O]

This helps in fuel mileage .
Years back , bungee webs ,were all the rage with pickup truck people .
thousands of folks took off their tailgate and installed huge bungee webs and cargo nets instead of the tailgate.
All sorts of claims were made about improved economy .
Finally some folks put the (sales ) theory to the test . Turns out the trucks with the factory tailgate still installed got significantly better mileage .

It takes about ten feet for air to start to recover once it hits and goes over the windshield, you're right, a tailgate down does nothing.

 

[jimbosride]

Ok..... this one doubles as a speed brake. If things get a little loose you just deploy the hood release.

 

[33 IMP]

Ok..... this one doubles as a speed brake. If things get a little loose you just deploy the hood release.

View attachment 1846085

THAT'S what I'm talkin about!

 

[Dennis H]

Trendy. Like black wheels right now.

 

[turbine68rt]

And electric Chargers

 

[Detective D]

Eh.
Some of it looks stupid. most of it is pointless. But it's someone elses car, and almost all of it is inspired from people seeing stuff on race cars and wanting to bring race cars into their lives.
As if no one on this board has ever done that?

It is different times, and different styles, but also different race car tech as street cars are not related to race cars at all anymore. Some kids sees a LeMans car decked out with aero and such and wants to put it on his street ride as a fan and enthusiast, well who cares. You don't need to put it on yours. It might be pointless, and actually make things worse because it added weight, but it is their car and they think it is cool and I like when people think cars are cool. Live and let live, look at the rat rods people build, or other sillyness in car culture like the "roll coal" guys.
Society is in love with telling other people what not to do on unimportant matters like this. There is some serious stuff going on in the world that needs a stop put to it. I don't think pointless race car inspired aero bits on some kids daily is one of those important things to worry about.

 

[Coelacanth]

The point of this stuff is to shoot the sh!t and share opinions. Without that, I'd imagine most of the topics on here would disappear.

 

[72redbird]

You know, I never really noticed the notch until I read this thread, now I'm looking at every dang one!!!