F1 in Schools Dragster v2.0 CFD Analysis

After reviewing the Caedium RANS Flow results posted in "CFD Analysis of an F1 in Schools Dragster," Brett Sizeland, Basilisk Performance team's chief designer, has been busy updating his F1 in Schools CO2 dragster design. Using the same geometry preparation process, physics setup, and post-processing, all within Caedium's unified simulation environment, we were able to rapidly perform the new simulation and extract the flow results presented here.

F1 in Schools v2.0 DragsterF1 in Schools v2.0 Dragster

Physics

The flow conditions and turbulence model were identical to the previous case:

  • Free-stream air speed and moving-ground speed = 22 m/s
  • Wheel rotation speed = 16,307 rpm = 97,804 deg/s
  • CO2 jet speed (assuming nozzle diameter = 4 mm) = 154 m/s
  • k-omega SST

Results

Rear View of VelocityRear View of Velocity

Front View of PressureFront View of Pressure

Rear View of PressureRear View of Pressure

Front View of StreamlinesFront View of Streamlines

Rear View of StreamlinesRear View of Streamlines

Drag and lift monitors were created in Caedium for the car, and a comparison with the previous simulation results is shown in the table below:

Quantity Previous Design Current Design
Drag (N) 0.332 0.318
Lift (N) 0.06 0.2

Conclusion

The new dragster design has a much smoother flow around the wheels when compared to the previous design, as shown by the velocity vectors and streamlines. This improvement likely accounts for the lower drag of the new design.

Interestingly the lift of the new design is significantly higher than the previous design. This shouldn't be a problem as long as it is significantly less than the weight of the car in order to avoid the car taking off. The extra lift may be a benefit, as it will reduce the frictional forces (which are proportional to the weight of the car) between the wheels and the ground.

Try For Yourself

The sym project file for this study can be viewed in Caedium or you can investigate this case yourself using our RANS Flow add-on.

The most convenient way to view and edit this case is to use our Professional add-on that combines all the add-ons used during this example.

Comments

velocity contours

Hi Rich,

I have a question about the velocity contours. I assume you mapped off surface velocities to the surface, since for a NS solution the actual surface velocities, except for the wheels, are zero. How far off from the surface were the velocity samples taken?

Martin

Velocity Interpolation

As you rightly assumed, the velocity vectors are interpolated from the field values (cell-centers to nodes), so in terms of the surface the values come from the nearest cells. Also this simulation was performed with wall functions (high Reynolds number turbulence model), so the first cell heights are not too close to the walls, though they are within the log-law region.

Turn around time

Hi Rich,

Can you elaborate a little on what it took to solve the problem in terms of the type of machine/processor, how many cores, how much memory, and how many grid points. Also, how many iterations did it take before you reached your solution and how long (wall clock) did it take?

Thanks,
Martin

Statistics

I wasn't planning on this being a benchmark, but here goes:

Machine

  • OS: 32-bit Windows Vista Home Premium SP2
  • Laptop: HP Pavilion dv6000 circa April, 2007
  • Processor: Intel Core 2 CPU T5300@1.73 GHz
  • RAM: 2 GB
  • Graphics: NVIDIA GeForce Go 7400

Case

  • Cell Count: 270,225
  • Face Count: 553,364
  • Point Count: 52,115
  • Solver Process: 150 MB
  • Caedium Process: 109 MB
  • Approx. Wall Time per 10 Iterations: 100 secs
  • Max iterations: 400 (though the lift and drag where essentially converged after 200)
  • Total Time for 400 Iterations = 66 mins 40 secs

Australian Champions

Keen to see how this design fared in the heat of competition? Then see "New Australian F1 in Schools Champions Helped by Caedium."

student working on a dragster

i love the desien but what is the intier blue prints of this dragster there is harly any work shown in the basilick
all that is there is just the arodinamick no grafs no #s no work what so ever so can u please send me the hole work and dimentions along with the softwar to this racer and pics 2. also i will need some sort of paper saying that im allowed to us this disien. please send me this hole paper and every thing that i have asked for to
c1e1e6 Enmen Cresent Prince Edward Island Canada

senserly. Brandon Bernard

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