Kingske

Well-Known Member
First Name
Frank
Joined
Jun 6, 2020
Messages
903
Reaction score
984
Location
New Jersey, USA
Vehicles
2020 Porsche Taycan 4S, 2014 BMW 3 GT
Country flag
Hi @Kingske
We didn't run a back-to-back simulation with & without air curtain, so I don't have info on the real difference. But I would guess it's in the order of magnitude of 1%.

I've attached a screenshot below where you can at least see an indication that the flow through the air curtain (blue arrow) is reducing the wake/turbulent area around the lower part of the tire.

But we have to be careful with conclusions, as we don't have a car model with blocked curtains and this lower area might see reduced wake because of other reasons.


1622724324897.png

Nevertheless, we do see proper airflow going through the air curtains, so if it's blocked, for sure there is at least some impact!

1622725556124.png
@Wouter Remmerie , thank you.
Advertisement

 

BeTay22

Active Member
Joined
Sep 7, 2020
Messages
30
Reaction score
8
Location
Belgium
Vehicles
2007 BMW X5 while waiting for more high-power chargers
Country flag
I've attached a screenshot below where you can at least see an indication that the flow through the air curtain (blue arrow) is reducing the wake/turbulent area around the lower part of the tire.
Actually, the motorized charge port only blocks the rear air vent, the one between the front wheel and the door. So I guess the impact is probably even less?
 
OP
OP
First Name
Wouter
Joined
Jun 2, 2021
Messages
11
Reaction score
26
Location
Belgium
Vehicles
Taycan 4S
Country flag
Actually, the motorized charge port only blocks the rear air vent, the one between the front wheel and the door. So I guess the impact is probably even less?
That indeed makes things different:
I'm guessing the "rear" air vent is mainly there to evacuate some high pressure air from the wheel well and perhaps create a better attached flow on the side flank. I'm guessing (again, haven't done a sim with & without that) the order of magnitude of effect would be similar (1% or so). I think the car we tested had that vent closed, but I'm not sure (we'll discuss tufts in that area in the next video!)
 

JimBob

Well-Known Member
First Name
James
Joined
Jan 26, 2021
Messages
444
Reaction score
512
Location
Toronto Canada
Vehicles
Taycan 4S
Country flag
Do you know what changes if any occur under the two cases where the front cooling vents are open or closed.
 
OP
OP
First Name
Wouter
Joined
Jun 2, 2021
Messages
11
Reaction score
26
Location
Belgium
Vehicles
Taycan 4S
Country flag
Do you know what changes if any occur under the two cases where the front cooling vents are open or closed.
Hi Jim,

no, we don't have 3D models with the vents both open and closed.

I would guess an open vent helps to evacuate some of the high pressure from inside the wheel well and feed it into the turbulent area behind the wheel. And perhaps the grid/maze/... structure inside such vent can help make the flow a bit more laminar again, facilitating a more attached flow at the flanks?
 

JimBob

Well-Known Member
First Name
James
Joined
Jan 26, 2021
Messages
444
Reaction score
512
Location
Toronto Canada
Vehicles
Taycan 4S
Country flag
Hi Jim,

no, we don't have 3D models with the vents both open and closed.

I would guess an open vent helps to evacuate some of the high pressure from inside the wheel well and feed it into the turbulent area behind the wheel. And perhaps the grid/maze/... structure inside such vent can help make the flow a bit more laminar again, facilitating a more attached flow at the flanks?
Actually referring to the front cooling vents above the splitter. Used for cooling the batteries. When closed the Cd is .22 when open higher.
 
OP
OP
First Name
Wouter
Joined
Jun 2, 2021
Messages
11
Reaction score
26
Location
Belgium
Vehicles
Taycan 4S
Country flag
Actually referring to the front cooling vents above the splitter. Used for cooling the batteries. When closed the Cd is .22 when open higher.
Oh my bad, misunderstood your question!

The answer is the same in terms of 3D model:
we'd need one with open & closed vents.

On top of that, the internal modelling of the cooler is quite complex. Often, this is done using a "porous" block, which features a uniform flow resistance (rather than modelling the flow through the thousands of small openings in the cooler). This would be essential to assess the true difference!

Many other manufacturers apply this "trick" of closing the vents, so I'm guessing it's at least worth the extra weight & cost & development effort of the mechanism to do this.
 
Advertisement

 
ZYRUS
Advertisement
Top