Mercedes W13

[Just_a_fan]

Porpoising:
1) Is not that related to the surface the car run on. It's 90% an aerodynamic issue
2) Is caused by the flow choking at the back of the car, t-tray has minimum effect

Also damping the porpoising in a generic sense is not the solution. It is an instability, not just a bump on the road: damping will not fix the issue, it will at best limit it, but compromising the optimal damping required by the mechanics of the car.

The issue is the flow through the throat of the underfloor which is near the middle of the wheelbase, not at the rear end of the car.

flow at the rear will effect flow at the throat.
A f1 car is not made up of isolated components. there is plenty interaction.

The flow isn't "choking" at the rear. The "choking" occurs in the throat.

[Mchamilton]

Still bouncing, even though the surface is much smoother. They still don't have an answer. I wonder if they missed the damper trick ala Ferrari and HAAS on the t-tray

Porpoising:
1) Is not that related to the surface the car run on. It's 90% an aerodynamic issue
2) Is caused by the flow choking at the back of the car, t-tray has minimum effect

Also damping the porpoising in a generic sense is not the solution. It is an instability, not just a bump on the road: damping will not fix the issue, it will at best limit it, but compromising the optimal damping required by the mechanics of the car.

Surely the porpoising is to do with the vortices in the tunnels bursting when the floor gets too close to the ground

[matteosc]

The issue is the flow through the throat of the underfloor which is near the middle of the wheelbase, not at the rear end of the car.

flow at the rear will effect flow at the throat.
A f1 car is not made up of isolated components. there is plenty interaction.

The flow isn't "choking" at the rear. The "choking" occurs in the throat.

Agree, but it is a consequence of the car (particularly the rear) getting lower.

[NicoS]

The issue is the flow through the throat of the underfloor which is near the middle of the wheelbase, not at the rear end of the car.

flow at the rear will effect flow at the throat.
A f1 car is not made up of isolated components. there is plenty interaction.

The flow isn't "choking" at the rear. The "choking" occurs in the throat.

Flow at the rear will effect flow at the front. it's not to isolated systems.
like a hose, you block the outlet, you choke the inlet, simple.

[PlatinumZealot]

Still bouncing, even though the surface is much smoother. They still don't have an answer. I wonder if they missed the damper trick ala Ferrari and HAAS on the t-tray

Porpoising:
1) Is not that related to the surface the car run on. It's 90% an aerodynamic issue
2) Is caused by the flow choking at the back of the car, t-tray has minimum effect

Also damping the porpoising in a generic sense is not the solution. It is an instability, not just a bump on the road: damping will not fix the issue, it will at best limit it, but compromising the optimal damping required by the mechanics of the car.

Surely the porpoising is to do with the vortices in the tunnels bursting when the floor gets too close to the ground

Watching the Redbull today, it was slightly porpoising on almost all the straights. I think the forces above the car also contribute to the bouncing. I'm thinking the porpoising gets amplified because of the natural springiness of the suspension.

[Mchamilton]

Porpoising:
1) Is not that related to the surface the car run on. It's 90% an aerodynamic issue
2) Is caused by the flow choking at the back of the car, t-tray has minimum effect

Also damping the porpoising in a generic sense is not the solution. It is an instability, not just a bump on the road: damping will not fix the issue, it will at best limit it, but compromising the optimal damping required by the mechanics of the car.

Surely the porpoising is to do with the vortices in the tunnels bursting when the floor gets too close to the ground

Watching the Redbull today, it was slightly porpoising on almost all the straights. I think the forces above the car also contribute to the bouncing. I'm thinking the porpoising gets amplified because of the natural springiness of the suspension.

Oh for sure the forces above the car cobtirbute to car lowering to the point where the underfloor flow breaks down.
They cut the bottom of the inner moat strake didnt they, can only assume that was an attempt to alter position/strength of the vortex that would be rolled up on the inboard side of it.

[PlatinumZealot]

Yeah, so I am suggesting the proposing can be reduced if the teams design the upper part of the car to be a bit more on on the stable side.. as in less aggressive cambers on the wings so that slight displacements don't change the lift/drag too much.

[Just_a_fan]

flow at the rear will effect flow at the throat.
A f1 car is not made up of isolated components. there is plenty interaction.

The flow isn't "choking" at the rear. The "choking" occurs in the throat.

Flow at the rear will effect flow at the front. it's not to isolated systems.
like a hose, you block the outlet, you choke the inlet, simple.

And how is the rear of the car choking the throat on the Mercedes?

[matteosc]

Yeah, so I am suggesting the proposing can be reduced if the teams design the upper part of the car to be a bit more on on the stable side.. as in less aggressive cambers on the wings so that slight displacements don't change the lift/drag too much.

The porpoising is caused by alternate loss and gain of downforce occurring when the floor gets too close to the ground and when it gets back up respectively. The load generated by the upper part of the car does not suffer from this effect. The reason why we see this effect this year is that a way larger portion of the downforce comes from the floor.

[AR3-GP]

Yeah, so I am suggesting the proposing can be reduced if the teams design the upper part of the car to be a bit more on on the stable side.. as in less aggressive cambers on the wings so that slight displacements don't change the lift/drag too much.

This is incredibly speculative.

[AR3-GP]

Yeah, so I am suggesting the proposing can be reduced if the teams design the upper part of the car to be a bit more on on the stable side.. as in less aggressive cambers on the wings so that slight displacements don't change the lift/drag too much.

The porpoising is caused by alternate loss and gain of downforce occurring when the floor gets too close to the ground and when it gets back up respectively. The load generated by the upper part of the car does not suffer from this effect. The reason why we see this effect this year is that a way larger portion of the downforce comes from the floor.

It's coming from the suspension too. Undamped heave mode.

[bonjon1979]

Haven’t you guys fixed it already? Jeez!

[NicoS]

The flow isn't "choking" at the rear. The "choking" occurs in the throat.

Flow at the rear will effect flow at the front. it's not to isolated systems.
like a hose, you block the outlet, you choke the inlet, simple.

And how is the rear of the car choking the throat on the Mercedes?

sidepods optimised for downwash, not directing enough flow over diffuser, lack of low pressure over diffuser, resulting in less effective evacuation of air from under car, thus chocking channels.

[Mchamilton]

Yeah, so I am suggesting the proposing can be reduced if the teams design the upper part of the car to be a bit more on on the stable side.. as in less aggressive cambers on the wings so that slight displacements don't change the lift/drag too much.

The porpoising is caused by alternate loss and gain of downforce occurring when the floor gets too close to the ground and when it gets back up respectively. The load generated by the upper part of the car does not suffer from this effect. The reason why we see this effect this year is that a way larger portion of the downforce comes from the floor.

It's coming from the suspension too. Undamped heave mode.

How is it 'coming from' the suspension? The suspension is moving as a consequence of the changing load under the car.
Its that severe change in the load that needs to be better controlled.

[Mchamilton]

Flow at the rear will effect flow at the front. it's not to isolated systems.
like a hose, you block the outlet, you choke the inlet, simple.

And how is the rear of the car choking the throat on the Mercedes?

sidepods optimised for downwash, not directing enough flow over diffuser, lack of low pressure over diffuser, resulting in less effective evacuation of air from under car, thus chocking channels.

Not directing enough flow over the diffuser? Have you seen the sheer amount of exposed floor there is on this car?