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XX株式会社殿¶

TR-23-0026¶

TS01 Automotive Wind Tunnel Test Report¶

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Test Condition¶

• Date & Time of Test: 4/14/2023
• Measured Sample: Automobile 12U
• Refer to Attached Test Conditions for each RUN no. detail and overview.

RUN No.¶

• Data is shown for Run No.: 006~008: Base Configuration with Spoiler deployed. and RUN011~013: Same configuration re-run.
• Refer to Attached Test Conditions for each RUN no. detail and overview.

Table of Contents¶

• Table of Contents
• Analysis Options
• Analysis Result
• Results for RUNs 006-008
• Results for RUNs 011-013
• Conclusion

Analysis Options¶

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Data Normalizing¶

• [ - ] Normalized with Flow Velocity (Standard 15.0m/s)
• [ - ] Normalized with Flow Velocity and Density (Standard 1.225 kg/m3)
• [ N ] Normalizing not used

Options¶

• [ Y ] Basic Data Analysis
• [ - ] Smoke Visualization Option
• [ - ] Tuft Visualization Option
• [ - ] High Speed Imaging
• [ Y ] Data Filtering
• [ Y ] FFT Analysis
• [ - ] Discussions

Calculation Definitions¶

• No custom functions.

Filter Settings¶

• Sampling Rate: 100Hz
  
• Low Pass Gauss Filter (LPF) Frequency: 10Hz
  
• High Pass Filter (HPF) Frequency: 15Hz
  

Analysis Result¶

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Definitions¶

• DateName: Name of RUN Number
• Velocity_Ave: Average Wind Speed in [m/s]
• Pitot_Ave: Average Pitot tube dynamic pressure in [Pa]
• CdA: Cd x Frontal Area [m2]
• ClA: Cl x Frontal Area [m2]
• Drag_N_Ave: Average Drag in [N]
• LF_N_Ave: Average Frontal Lift in [N]
• LR_N_Ave: Average Rear Lift in [N]
• SF_N_Ave: Average Side Force in [N]

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• XXX_stdev: Standard Deviation during each RUN for data XXX

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• XXX_HPF_stdev: Standard Deviation of HPF applied RUN data
• XXX_HPF_Ave: Average value of HPF applied RUN data. 0 means fully random noise.

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Results for RUNs 006-008¶

Gauss Filtered Averaged Values each RUN: (m/s),(N)¶

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Gauss Dynamic Pressures (Pa)¶

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STD Deviations each RUN LPF:¶

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STD Deviations Random Noise HPF>cutoff freq.:¶

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Summary of RUNs¶

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Average and stdev Summary of all RUNS

Definitions¶

• Mass: Vehicle Total Mass [kg]
• CG_x: Center of gravity in Drag direction. 0=CG at vehicle wheelbase centerline, +is in aft direction. [m]
• CG_y: Center of gravity in Side direction. 0=CG at vehicle tread centerline. [m]
• CG_z: Center of gravity height. Cannot be measured by this system.
• FL_weight: Corner weight value at Front Left Wheel [kg]
• FR_weight: Corner weight value at Front Right Wheel [kg]
• RL_weight: Corner weight value at Rear Left Wheel [kg]
• RR_weight: Corner weight value at Rear Right Wheel [kg]

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• F-R_WtBalance: Front to Rear Weight Balance [-]
• R-L_WtBalance: Right to Left Weight Balance [-]
• Velocity_Ave: Average Wind Speed [m/s]
• Velocity_stdev: Velocity standard deviation [m/s]
• Air_Density: Average Air Density [kg/m3]
• L/D: Vehicle Lift to Drag Ratio[N/N]

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• Pitot_Ave_HPF_stdev: Standard Deviation of Pitot tube dynamic pressure HPF applied values [Pa]
• Pitot_Ave_HPF_Ave: Average of Pitot tube dynamic pressure HPF applied values. 0 means fully random noise [Pa]
• Drag_N_Ave: Average Drag in [N]
• Drag_N_stdev: Standard Deviation of Drag in [N]
• Lift_N_Ave: Average Lift in [N]
• Lift_N_stdev: Standard Deviation of Lift in [N]
• SF_N_Ave: Average Side Force in [N]
• SF_N_stdev: Standard Deviation of Side Force in [N]
• LF_N, LR_N: Frontal and Read Lifts respectively [N]

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• Cp_x: Center of Pressure in x direction. 0= at vehicle wheelbase centerline, applicable only to downforce generating cars [m]
• CD_x: Center of Drag in x direction. [m]
• X_CpCG: Distance between CG (CoG) and Cp_x [m]
• X_CDCG: Distance between CG (CoG) and CD_x [m]
• PM: Pitching Moment around vehicle CG_x [Nm]
• YM: Yawing Moment around vehicle CG_x [Nm]
• RM: Roll Moment around vehicle CG_x [Nm]

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• Drag_N_Norm: Normalized Drag. Applicable only when Normalize option is specified. [N]
• Lift_N_Norm: Normalized Lift. Applicable only when Normalize option is specified. [N]

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Average and Standard Deviation for all RUNs (Applicable only to Same Wind Speed)¶

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Measured Data Values¶

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FFT Result¶

Results for RUNs 011-013¶

Gauss Filtered Averaged Values each RUN: (m/s),(N)¶

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Gauss Dynamic Pressures (Pa)¶

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STD Deviations each RUN LPF:¶

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STD Deviations Random Noise HPF>cutoff freq.:¶

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Average and Standard Deviation for all RUNs (Applicable only to Same Wind Speed)¶

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Measured Data Values¶

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FFT Result¶

Conclusion¶

Discussions¶

• Vehicle exhibits hight lift without the use of active rear spoiler. The rear spoiler is essential to maintain stability during high speed.
• The vehicle has an extremely low drag coefficient which may be further improved by the use of a more efficient rear spoiler.
• Vehicle natural frequency is at 1.8Hz, 4Hz and 7Hz. Frequencies emerge constantly with good reproductivity. The vibration level is very low with most values under 15N^2/Hz
• Due to the extreme front toe-out geometry, a gain in side force is obsereved when drag is applied to the vehicle.

Conclusions and Recommendations¶

• Increased frontal downforce should be considered by use of a front splitter for improved stability.
• The rear spoiler is effective is creating a large amount for rear downforce, however has a low L/D coefficient. A larger wing area with laminar flow should be considered for improved drag and rear downforce.
• Frontal geometry shall be reconsidered. The extreme toe-out geometry causes a high amount of friction and instability.
• Improvements to the strut suspension may be considered by adding stiffer bushings to further improve compliance.

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2023 Japan Wind Tunnel Testing Inc.