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I have no sway here... But just acting as a Mediator; could you accept Option 1 for the early races and then switch to option 2 when it gets sorted... This would mean you could start work now....???That is why I would accept the opt1+ compromise for this year (maybe for the first 2 races only?), also considering that we have about one month to complete the car design and we actually need the definitive rulebook. For the same reason I would accept to keep the ride height as it is, waiting next year to discuss about it.
Sure I can! I would accept anything in any casemachin wrote:I have no sway here... But just acting as a Mediator; could you accept Option 1 for the early races and then switch to option 2 when it gets sorted... This would mean you could start work now....???That is why I would accept the opt1+ compromise for this year (maybe for the first 2 races only?), also considering that we have about one month to complete the car design and we actually need the definitive rulebook. For the same reason I would accept to keep the ride height as it is, waiting next year to discuss about it.
I'll discuss this with Julien - it might make things easier.CAEdevice wrote:I would keep:
- the heat exchanger template (200000-250000 mm2) and 30° rotation freedom (or increased to 45°)
- the normal extrusion (100mm): the volume between front and rear heat exchanger surfaces will be part of the body
- the required flow through the heat exchanger (2016 or 2017 value)
... but I would apply the "flow boundary condition" directly to the virtual heat exchanger surfaces and then I would compute the pressure differential between the heat exchanger surfaces.
In a few words: a compromise between Opt1 and Opt2, taking the computation simplicity from Opt1 and the design freedom from Opt2.
Ok for everything! Talking on the forum with Machin, I realized that the floor distance from the ground it is not only a issue about distance (I still think that minumum distance should be lowered) but also about rake: it woould be a too big change for this season.cdsavage wrote:Getting ready to release the definitive rulebook:
- Ride height will be staying unchanged for 2016. Maybe we can change this for 2017.
- The guide file for full entries that was released a while ago can probably be considered final at this point.
- Subclass: no engine exhausts were included in the supplied bodywork, leaving open the option to place the exhausts in an aerodynamically beneficial area. For simplicity, since the other three inlet/outlet surfaces are included, I propose including the exhaust outlets in the supplied bodywork in a fairly neutral position (ahead of the rear wheels), so that all inlet/outlet surfaces are already modeled for subclass entries.
- 230K was the planned size for "option 2", but I agree that with the 100mm extrusion, 230K is still a bit too large. I am checking with Julien, but I would propose either:
1) 100mm extrusion -> 50mm, 230K area -> 225K
2) 100mm extrusion unchanged, 230K area -> 200K
Both with the 30 degree limit unchanged.
I would remove every limit except the heat exchanger dimension and thickness. Theoretically, we should be allowed to mount a naked heat exchanger directly exposed to the air. Rules should only limit the heat exchanger to make it realistic.cdsavage wrote:I'll discuss this with Julien - it might make things easier.
As for removing the rules on inlet and outlet surfaces for "option 2", I am thinking that for this first year with the new cooling rules, it would probably be best to keep these, even though those surfaces are for rules compliance only. If we were to free things up here, which part would you most want to remove? Would it be the minimum longitudinal distance from the inlets to the outlets?
I agree that in theory, there should be no need for restrictions on inlet/outlet area for option 1, and there should be no need to define inlet and outlet surfaces for option 2. But since we don't have any experience with these rules yet, we wanted to include some 'sanity checks'. If everything goes really well then I think we would definitely look at removing all of these aspects for 2017. For now though, I think it would be a risk to remove all of them. Perhaps we can loosen one or two specific restrictions if there are any that are a particular pain to comply with.CAEdevice wrote:I would remove every limit except the heat exchanger dimension and thickness. Theoretically, we should be allowed to mount a naked heat exchanger directly exposed to the air. Rules should only limit the heat exchanger to make it realistic.cdsavage wrote:As for removing the rules on inlet and outlet surfaces for "option 2", I am thinking that for this first year with the new cooling rules, it would probably be best to keep these, even though those surfaces are for rules compliance only. If we were to free things up here, which part would you most want to remove? Would it be the minimum longitudinal distance from the inlets to the outlets?
The same for the inlet area of opt1 (not the same with the outlet area , because it could be an advantage to "not model the outlet" at all, zero area I mean.
About the 2016-2017 transition: my brief experience with the simulations I've done (OCCFD opt1, but most of the ideas are still valid for opt2) makes me think that to rule the ducts in order to have a mimimum inlet area is not a big help. A well oriented flow could work even if the inlet area il 25000mm2, on the contrary, a wrong design will not work even if the inlet area il 100000m2
OK, it would be important to receive a feedback from other partecipants.cdsavage wrote:I agree that in theory, there should be no need for restrictions on inlet/outlet area for option 1, and there should be no need to define inlet and outlet surfaces for option 2. But since we don't have any experience with these rules yet, we wanted to include some 'sanity checks'. If everything goes really well then I think we would definitely look at removing all of these aspects for 2017. For now though, I think it would be a risk to remove all of them. Perhaps we can loosen one or two specific restrictions if there are any that are a particular pain to comply with.
I would be fine with both options but prefer 2.cdsavage wrote: - 230K was the planned size for "option 2", but I agree that with the 100mm extrusion, 230K is still a bit too large. I am checking with Julien, but I would propose either:
1) 100mm extrusion -> 50mm, 230K area -> 225K
2) 100mm extrusion unchanged, 230K area -> 200K
Both with the 30 degree limit unchanged.
This is the part I do not like too much. Personaly I will have an issue creating these parts to comply with the currently strict rules. Using Blender and the way I design the car I am not sure how I will get this done. I know it is my own problem.cdsavage wrote:I agree that in theory, there should be no need for restrictions on inlet/outlet area for option 1, and there should be no need to define inlet and outlet surfaces for option 2. But since we don't have any experience with these rules yet, we wanted to include some 'sanity checks'. If everything goes really well then I think we would definitely look at removing all of these aspects for 2017. For now though, I think it would be a risk to remove all of them. Perhaps we can loosen one or two specific restrictions if there are any that are a particular pain to comply with.
For option 2, when the suspension templates intersect the duct, the intention is for there to not be any holes allowing the templates to pass through - the templates would intersect the bodywork. This would be similar to the first image shown in K2.6, but with an extra void inside the bodywork (the duct). This wasn't clear from the text in the rulebook, I need to make a change here.LVDH wrote:This is the part I do not like too much. Personaly I will have an issue creating these parts to comply with the currently strict rules. Using Blender and the way I design the car I am not sure how I will get this done. I know it is my own problem.cdsavage wrote:I agree that in theory, there should be no need for restrictions on inlet/outlet area for option 1, and there should be no need to define inlet and outlet surfaces for option 2. But since we don't have any experience with these rules yet, we wanted to include some 'sanity checks'. If everything goes really well then I think we would definitely look at removing all of these aspects for 2017. For now though, I think it would be a risk to remove all of them. Perhaps we can loosen one or two specific restrictions if there are any that are a particular pain to comply with.
However I do not quite see why we need these surfaces. If it is for CFD, then Julien will be able to confirm that he gets the flows more or less automatically reported. There is no need for additional surfaces. Also if you look at the design I showed yesterday, some flow would exit the rear wheel houses in through the suspension openings. How should that be monitored? And having a surface ahead of that would also be a bit difficult with the strict rules.
Would it be possible to just relax the rules on that? No penalties if the surface is not perfect?
Isn't it possible to use edge creasing to ensure that the surface passes exactly through the edge after it is smoothed?LVDH wrote:The difficulty is mainly, I think you, being very strict on perfectly matching surfaces.
The way I use Blender, my side pod, the engine cover, the floor and the body are separate bodies. So I cannot really make a surface that perfectly fits the triangulated duct openings.
Last year I once intentionally submitted the cooling and inlet surfaces a bit to big , slightly intersecting the surrounding geometries. My intention was to make snappyHexMesh's life a bit easier. That way it does not get confused and the small overlapping surfaces get removed during the meshing process.
Unfortunately I got a nice email with a minor rule violation.
Depending on how strict you want to stay here, I have a small problem although there is not performance gain in this surface.
But do not change the rules just for me. I could use an additional tool to create these surfaces, it would just be very annoying.
Something like this is what I'm thinking about: http://archive.blender.org/development/ ... index.html. I've used this in other polymodelling packages in the past to ensure that the smoothed surface passes exactly through the creased edge (when set to a value of 1).LVDH wrote:Not to my knowledge.
But if these surfaces are not for the CFD process, wouldn't it be enough to show that a surface with the minimal area requirements fits into the duct?