y-yosuke / formula-ppoino

A side-by-side two-seater car of the early 2000s formula style
Creative Commons Attribution 4.0 International
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More Front Downforce!! #12

Open y-yosuke opened 8 years ago

y-yosuke commented 8 years ago

CFDの結果を信じる限りにおいてはフロントのダウンフォースが足りないらしい. https://github.com/y-yosuke/formula-ppoino/issues/11#issuecomment-233866299

なのでフロントダウンフォースの増加策を考える. https://github.com/y-yosuke/formula-ppoino/issues/11#issuecomment-233886791 の続き.

CFD 解析をして大雑把な傾向を見ながら開発を進める.

とりあえず S-Duct ほい. 2016-07-22 1 35 41

y-yosuke commented 8 years ago

Front Fender Stay - Louver / Pressure fp-023c_cfd_fr-fender-stay-louver_p-01 fp-023c_cfd_fr-fender-stay-louver_p-02 fp-023c_cfd_fr-fender-stay-louver_p-03 fp-023c_cfd_fr-fender-stay-louver_p-04

y-yosuke commented 8 years ago

Front Fender Stay - Louver / fp-023c Control - Coefficients Comparison


Body and Wheels

Coef. fp-023c Control Fr Fender Stay Louver Difference Difference % Remarks
Cm 0.0781 0.0580 -0.0200 -25.7
Cd 0.5590 0.5594 +0.0004 +0.1
Cl -0.1693 -0.1856 -0.0164 -9.7
Clf -0.0066 -0.0348 -0.0282 -430.8
Clr -0.1627 -0.1509 +0.0118 +7.3
CoP 0.9613 0.8127 -0.1486 -14.9
L/D -0.3028 -0.3318 -0.0291 -9.6

Body Only

Coef. fp-023c Control Fr Fender Stay Louver Difference Difference % Remarks
Cm 0.0610 0.0397 -0.0212 -34.8
Cd 0.4385 0.4356 -0.0028 -0.6
Cl -0.2099 -0.2277 -0.0178 -8.5
Clf -0.0440 -0.0741 -0.0301 -68.5
Clr -0.1659 -0.1536 +0.0123 +7.4
CoP 0.7904 0.6745 -0.1159 -11.6
L/D -0.4787 -0.5227 -0.0440 -9.2
y-yosuke commented 8 years ago

S-Duct B / fp-023c Control (S-Duct) - Coefficients Comparison

Body and Wheels

Coef. fp-023c Control S-Duct B Difference Difference % Remarks
Cm 0.0781 0.0829 +0.0048 +6.2
Cd 0.5590 0.5599 +0.0009 +0.2
Cl -0.1693 -0.1698 -0.0006 -0.3
Clf -0.0066 -0.0020 +0.0045 +68.9
Clr -0.1627 -0.1678 -0.0051 -3.1
CoP 0.9613 0.9880 +0.0267 +2.7
L/D -0.3028 -0.3034 -0.0006 -0.2

Body Only

Coef. fp-023c Control S-Duct B Difference Difference % Remarks
Cm 0.0610 0.0657 +0.0047 +7.8
Cd 0.4385 0.4389 +0.0004 +0.1
Cl -0.2099 -0.2101 -0.0002 -0.1
Clf -0.0440 -0.0394 +0.0046 +10.5
Clr -0.1659 -0.1708 -0.0049 -2.9
CoP 0.7904 0.8126 +0.0222 +2.2
L/D -0.4787 -0.4788 -0.0001 -0.0

S-Duct B (N=800)

forces forces00 output:
sum of forces:
pressure : (193.182943654 -211.1175369 -64.6585533378)
viscous : (16.9342055983 -1.1612082756 0.918214639582)
porous : (0 0 0)
sum of moments:
pressure : (82.9307102155 73.2037344004 85.9220588796)
viscous : (-0.115295623349 9.22704317281 10.9899892581)
porous : (0 0 0)
forceCoeffs forceCoeffs02 output:
Cm = 0.0656816313594
Cd = 0.4388667238
Cl = -0.210138970477
Cl(f) = -0.0393878538793
Cl(r) = -0.170751116598
forceCoeffs forceCoeffs01 output:
Cm = 0.0828843945401
Cd = 0.559874576087
Cl = -0.169841420538
Cl(f) = -0.00203631572878
Cl(r) = -0.167805104809
y-yosuke commented 8 years ago

S-Duct B / fp-023c Control (S-Duct) - Pressure and U-Magnitude Comparison

Surface Pressure fp-023c_s-duct-b_p-01 fp-023c_s-duct-b_p-02

Y=0mm Pressure fp-023c_s-duct-b_p-y000-01 Y=-120mm Pressure fp-023c_s-duct-b_p-y120-01

Y=0mm U-Magnitude fp-023c_s-duct-b_u-y000-01

y-yosuke commented 8 years ago

Coefficients Comparison for GitHub Issues - Google Drive Spreadsheet https://docs.google.com/spreadsheets/d/16RVkg4-Oiqgl5CmZgXSQ4busL_FCBbx4LxGmaFLLxrU/edit?usp=sharing

y-yosuke commented 8 years ago

Front Fender Louver C + Louver Stay / fp-023c Control - Coefficients Comparison


Body and Wheels

Coef. fp-023c Control Fr Fender Louver C + Louver Stay Difference Difference % Remarks
Cm 0.0781 0.0428 -0.0353 -45.2
Cd 0.5590 0.5683 +0.0093 +1.7
Cl -0.1693 -0.2051 -0.0358 -21.2
Clf -0.0066 -0.0598 -0.0532 -812.3
Clr -0.1627 -0.1453 +0.0174 +10.7
CoP 0.9613 0.7086 -0.2527 -25.3
L/D -0.3028 -0.3609 -0.0581 -19.2

Body Only

Coef. fp-023c Control Fr Fender Louver C + Louver Stay Difference Difference % Remarks
Cm 0.0610 0.0231 -0.0378 -62.0
Cd 0.4385 0.4433 +0.0049 +1.1
Cl -0.2099 -0.2586 -0.0487 -23.2
Clf -0.0440 -0.1061 -0.0622 -141.3
Clr -0.1659 -0.1524 +0.0135 +8.1
CoP 0.7904 0.5895 -0.2009 -20.1
L/D -0.4787 -0.5833 -0.1046 -21.8

Front Fender Louver C + Louver Stay (N=800)

forces forces00 output:
sum of forces:
pressure : (195.849018972 -213.976414436 -78.0798080457)
viscous : (17.4363679765 -1.06542027951 1.11178466513)
porous : (0 0 0)
sum of moments:
pressure : (90.8645614662 32.6684863908 90.3038405582)
viscous : (-0.300541654383 9.87526980512 11.4990146828)
porous : (0 0 0)
forceCoeffs forceCoeffs02 output:
Cm = 0.0231455610287
Cd = 0.443333425557
Cl = -0.258590762715
Cl(f) = -0.106149820329
Cl(r) = -0.152440942386
forceCoeffs forceCoeffs01 output:
Cm = 0.0427778746916
Cd = 0.568316608275
Cl = -0.20508768378
Cl(f) = -0.0597659671982
Cl(r) = -0.145321716581
y-yosuke commented 8 years ago

Front Fender Louver C + Louver Stay - Flow Vector

Slice at Y=-520mm fp-023c_cfd_fr-fender-louver-c_louver-stay_vt-sly520-01 fp-023c_cfd_fr-fender-louver-c_louver-stay_vt-sly520-02

y-yosuke commented 8 years ago

Front Fender Louver C + Louver Stay B / Front Fender Louver C + Louver Stay - Coefficients Comparison


Body and Wheels

Coef. Fr Fender Louver C + Louver Stay Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0428 0.0496 +0.0068 +15.8
Cd 0.5683 0.5622 -0.0061 -1.1
Cl -0.2051 -0.1990 +0.0061 +3.0
Clf -0.0598 -0.0499 +0.0098 +16.5
Clr -0.1453 -0.1490 -0.0037 -2.5
CoP 0.7086 0.7491 +0.0405 +4.0
L/D -0.3609 -0.3539 +0.0070 +1.9

Body Only

Coef. Fr Fender Louver C + Louver Stay Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0231 0.0300 +0.0068 +29.5
Cd 0.4433 0.4401 -0.0033 -0.7
Cl -0.2586 -0.2515 +0.0071 +2.7
Clf -0.1061 -0.0958 +0.0104 +9.8
Clr -0.1524 -0.1557 -0.0033 -2.2
CoP 0.5895 0.6192 +0.0297 +3.0
L/D -0.5833 -0.5716 +0.0117 +2.0

Front Fender Louver C + Louver Stay B (N=800)

forces forces00 output:
sum of forces:
pressure : (193.594173988 -212.110703092 -75.7760171924)
viscous : (17.3917652795 -1.08442962181 1.11069449078)
porous : (0 0 0)
sum of moments:
pressure : (89.2308128353 39.431771951 87.3466997841)
viscous : (-0.291788799091 9.8484672478 11.4303927196)
porous : (0 0 0)
forceCoeffs forceCoeffs02 output:
Cm = 0.0299764568244
Cd = 0.440050754546
Cl = -0.251531019826
Cl(f) = -0.0957890530888
Cl(r) = -0.155741966738
forceCoeffs forceCoeffs01 output:
Cm = 0.0495514285929
Cd = 0.562189539161
Cl = -0.198951946782
Cl(f) = -0.049924544798
Cl(r) = -0.149027401984
y-yosuke commented 8 years ago

Front Fender Louver C + Louver Stay B /Front Fender Louver C + Louver Stay Flow Vector, U-Magnitude, Pressure Comparison

Flow Vector - Slice at Y=-520mm fp-023c_cfd_fr-fender-louver-stay-b_vt-sly520-01

U Magnitude - Slice at Y=-520mm fp-023c_cfd_fr-fender-louver-stay-b_um-sly520-01 1 13 57 fp-023c_cfd_fr-fender-louver-stay-b_um-sly520-02

Pressure on the body fp-023c_cfd_fr-fender-louver-stay-b_p-01 fp-023c_cfd_fr-fender-louver-stay-b_p-02

y-yosuke commented 8 years ago

Front Fender Louver C + Louver Stay B / fp-023c Control - Coefficients Comparison


Body and Wheels

Coef. fp-023c Control Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0781 0.0496 -0.0285 -36.5
Cd 0.5590 0.5622 +0.0032 +0.6
Cl -0.1693 -0.1990 -0.0297 -17.5
Clf -0.0066 -0.0499 -0.0434 -662.1
Clr -0.1627 -0.1490 +0.0137 +8.4
CoP 0.9613 0.7491 -0.2122 -21.2
L/D -0.3028 -0.3539 -0.0511 -16.9

Body Only

Coef. fp-023c Control Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0610 0.0300 -0.0310 -50.8
Cd 0.4385 0.4401 +0.0016 +0.4
Cl -0.2099 -0.2515 -0.0416 -19.8
Clf -0.0440 -0.0958 -0.0518 -117.7
Clr -0.1659 -0.1557 +0.0102 +6.1
CoP 0.7904 0.6192 -0.1712 -17.1
L/D -0.4787 -0.5716 -0.0929 -19.4
y-yosuke commented 8 years ago

Ride Height Analysis 110mm - 110mm : Done 90mm - 110mm : Done

One more run, which set should I choose? 90mm - 90mm? 90mm - 100mm? 80mm - 100mm? 70mm - 90mm? 70mm - 100mm?

y-yosuke commented 8 years ago

Probably 90-90.

y-yosuke commented 8 years ago

Ride Height : Front 90mm - Rear 110mm / Front 110mm - Rear 110mm Coefficients Comparison(fp-023c Control + Front Fender Louver C + Louver Stay B)


Body and Wheels

Coef. RH110-110 RH90-110 Difference Difference % Remarks
Cm 0.0496 0.0221 -0.0274 -55.3
Cd 0.5622 0.5641 +0.0020 +0.3
Cl -0.1990 -0.2544 -0.0554 -27.9
Clf -0.0499 -0.1051 -0.0551 -110.4
Clr -0.1490 -0.1493 -0.0003 -0.2
CoP 0.7491 0.5870 -0.1621 -16.2
L/D -0.3539 -0.4509 -0.0970 -27.4

Body Only

Coef. RH110-110 RH90-110 Difference Difference % Remarks
Cm 0.0300 0.0036 -0.0264 -88.1
Cd 0.4401 0.4380 -0.0021 -0.5
Cl -0.2515 -0.3013 -0.0498 -19.8
Clf -0.0958 -0.1471 -0.0513 -53.6
Clr -0.1557 -0.1542 +0.0015 +1.0
CoP 0.6192 0.5118 -0.1073 -10.7
L/D -0.5716 -0.6880 -0.1164 -20.4

Ride Height Front 90mm - Rear 110mm - Front Fender Louver C + Louver Stay B (N=800)

forces forces00 output:
sum of forces:
pressure : (194.291186818 -213.825979718 -96.6543773514)
viscous : (17.4300011885 -1.07900206673 1.19017166119)
porous : (0 0 0)
sum of moments:
pressure : (95.3464649842 12.3364344072 86.3704867995)
viscous : (-0.351573823555 9.66856081282 11.492471991)
porous : (0 0 0)
forceCoeffs forceCoeffs02 output:
Cm = 0.00356647633311
Cd = 0.437982707814
Cl = -0.301326842985
Cl(f) = -0.14709694516
Cl(r) = -0.154229897826
forceCoeffs forceCoeffs01 output:
Cm = 0.0221260888149
Cd = 0.564148670425
Cl = -0.254372296039
Cl(f) = -0.105060059204
Cl(r) = -0.149312236834
y-yosuke commented 8 years ago

Ride Height : Front 90mm - Rear 110mm / Front 110mm - Rear 110mm U Magnitude, Pressure Comparison ( fp-023c Control + Front Fender Louver C + Louver Stay B )

U Magnitude : Slice at Y=-800mm fp-023c_cfd_rh90-110_fr-fender-louver-c-louver-stay-b_um-sly800mm-01 fp-023c_cfd_rh90-110_fr-fender-louver-c-louver-stay-b_um-sly800mm-02 fp-023c_cfd_rh90-110_fr-fender-louver-c-louver-stay-b_um-sly800mm-03

U Magnitude : Slice at Y=0mm fp-023c_cfd_rh90-110_fr-fender-louver-c-louver-stay-b_um-sly0mm-01

Pressure : Bottom View fp-023c_cfd_rh90-110_fr-fender-louver-c-louver-stay-b_p-01

y-yosuke commented 8 years ago

Ride Height : Front 90mm - Rear 90mm / Front 90mm - Rear 110mm Coefficients Comparison(fp-023c Control + Front Fender Louver C + Louver Stay B)


Body and Wheels

Coef. RH90-110 RH90-90 Difference Difference % Remarks
Cm 0.0221 0.0503 +0.0282 +127.3
Cd 0.5641 0.5562 -0.0080 -1.4
Cl -0.2544 -0.2487 +0.0057 +2.2
Clf -0.1051 -0.0741 +0.0310 +29.5
Clr -0.1493 -0.1746 -0.0253 -17.0
CoP 0.5870 0.7022 +0.1153 +11.5
L/D -0.4509 -0.4472 +0.0037 +0.8

Body Only

Coef. RH90-110 RH90-90 Difference Difference % Remarks
Cm 0.0036 0.0309 +0.0274 +767.2
Cd 0.4380 0.4362 -0.0018 -0.4
Cl -0.3013 -0.2923 +0.0091 +3.0
Clf -0.1471 -0.1152 +0.0319 +21.7
Clr -0.1542 -0.1771 -0.0228 -14.8
CoP 0.5118 0.6058 +0.0940 +9.4
L/D -0.6880 -0.6701 +0.0179 +2.6

Ride Height Front 90mm - Rear 90mm - Front Fender Louver C + Louver Stay B (N=800)

forces forces00 output:
sum of forces:
pressure : (191.36126958 -212.379017721 -94.5543844719)
viscous : (17.362086193 -1.03766758448 1.22020061593)
porous : (0 0 0)
sum of moments:
pressure : (92.4888905742 40.5730247486 88.3599140732)
viscous : (-0.397104898237 9.44665486222 11.446518923)
porous : (0 0 0)
forceCoeffs forceCoeffs02 output:
Cm = 0.0309300065483
Cd = 0.436155655602
Cl = -0.292254122391
Cl(f) = -0.115197054647
Cl(r) = -0.177057067744
forceCoeffs forceCoeffs01 output:
Cm = 0.0502949381491
Cd = 0.55616069773
Cl = -0.248696676149
Cl(f) = -0.0740533999252
Cl(r) = -0.174643276223
y-yosuke commented 8 years ago

Ride Height : Front 90mm - Rear 90mm / Front 110mm - Rear 110mm Coefficients Comparison(fp-023c Control + Front Fender Louver C + Louver Stay B)


Body and Wheels

Coef. RH110-110 RH90-90 Difference Difference % Remarks
Cm 0.0496 0.0503 +0.0007 +1.5
Cd 0.5622 0.5562 -0.0060 -1.1
Cl -0.1990 -0.2487 -0.0497 -25.0
Clf -0.0499 -0.0741 -0.0241 -48.3
Clr -0.1490 -0.1746 -0.0256 -17.2
CoP 0.7491 0.7022 -0.0468 -4.7
L/D -0.3539 -0.4472 -0.0933 -26.4

Body Only

Coef. RH110-110 RH90-90 Difference Difference % Remarks
Cm 0.0300 0.0309 +0.0010 +3.2
Cd 0.4401 0.4362 -0.0039 -0.9
Cl -0.2515 -0.2923 -0.0407 -16.2
Clf -0.0958 -0.1152 -0.0194 -20.3
Clr -0.1557 -0.1771 -0.0213 -13.7
CoP 0.6192 0.6058 -0.0133 -1.3
L/D -0.5716 -0.6701 -0.0985 -17.2
y-yosuke commented 8 years ago

atan(20/2650) = 0.432 [deg] Wheel Base : 2650 mm

y-yosuke commented 8 years ago

Ride Height : Front 90mm - Rear 90mm / Front 90mm - Rear 110mm U Magnitude Comparison(fp-023c Control + Front Fender Louver C + Louver Stay B)

Slice at Y=-1mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0001mm

Slice at Y=-100mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0100mm

Slice at Y=-200mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0200mm

Slice at Y=-300mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0300mm

Slice at Y=-400mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0400mm

Slice at Y=-500mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0500mm

Slice at Y=-600mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0600mm

Slice at Y=-700mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0700mm

Slice at Y=-800mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0800mm

Slice at Y=-900mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y0900mm

Slice at Y=-1000mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y1000mm

Slice at Y=-1100mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y1100mm

Slice at Y=-1200mm fp-023c_cfd_rh90-90_fr-fender-louver-c_louver-stay-b_um-sl-y1200mm

y-yosuke commented 8 years ago

fp-023c Control + Front Fender Louver C + Louver Stay B / Ride Height : 90-110mm Contour : k=7 (Turbulent kinetic energy value [m²/s²])

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k7_fr-left-01

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k7_rear-01

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k7_bottom-01

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k7_bottom-02

y-yosuke commented 8 years ago

fp-023c Control + Front Fender Louver C + Louver Stay B / Ride Height : 90-110mm Contour : k=10 [m^2/s^2]

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k10_01

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k10_02

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k10_03

fp-023c_cfd_rh90-110_fr-fender-louver-c_louver-stay-b_contour-k10_04

y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 1) 】

Front Fender Louvers

I found a low pressure area on the upper surface of the front fender. It seemed to generate a lift force like a aircraft wing coupled with the high pressure in the wheel house. So I thought that a louver may be effective for eliminating the pressure difference between the upper and lower surfaces of the front fender.

fp-023c_cfd_fr-fender_control_p-upr-surf

I tested 3 types of louver below in the simulations.

The shapes of these louvers are shown below along with the pressure value from the simulations.

fp-023c_cfd_fr-fender-louvers_p-surf

Coefficients comparison

A table comparing the coefficients obtained from the simulation are shown below. As it shows, "Fr Fender Louver C" is most effective with the biggest front downforce and the small drag increase.

Coefficients of the forces on the body and wheels

Coef. fp-023c Control Fr Fender Louver Fr Fender Louver B Fr Fender Louver C Remarks
Cm 0.0781 0.0696 0.0611 0.0600
Cd 0.5590 0.5619 0.5636 0.5619
Cl -0.1693 -0.1805 -0.1930 -0.1964
Clf -0.0066 -0.0206 -0.0354 -0.0383
Clr -0.1627 -0.1599 -0.1576 -0.1582
CoP 0.9613 0.8858 0.8168 0.8052
L/D -0.3028 -0.3212 -0.3424 -0.3496

Coefficients of the forces on the body (without wheels)

Coef. fp-023c Control Fr Fender Louver Fr Fender Louver B Fr Fender Louver C Remarks
Cm 0.0610 0.0512 0.0417 0.0406
Cd 0.4385 0.4430 0.4445 0.4418
Cl -0.2099 -0.2242 -0.2416 -0.2450
Clf -0.0440 -0.0609 -0.0791 -0.0819
Clr -0.1659 -0.1633 -0.1625 -0.1631
CoP 0.7904 0.7285 0.6726 0.6657
L/D -0.4787 -0.5060 -0.5434 -0.5546

Flow through the louver

These louvers generate flows from the lower side of front fender to upper as seen in the pictures below.

U Magnitude Comparison at Y=-800mm fp-023c_cfd_fr-fender-louvers_umag

Stream Lines - Front Fender Louver fp-023c_cfd_fr-fender-louver_stream

Stream Lines - Front Fender Louver B fp-023c_cfd_fr-fender-louver-b_stream

Stream Lines - Front Fender Louver C fp-023c_cfd_fr-fender-louver-c_stream

y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 2) 】

Front Fender Stay (Part 1)

I found the front fender stay was installed so as to go against the flow and it seemed to generate a lift force. Therefore I designed other stays that do not inhibit the flow.

fp-023c_cfd_fr-fender-stay_control

I tested 2 types of stays below in the simulations.

The shapes of these stays are shown below along with the pressure value from the simulations.

Upper View fp-023c_cfd_fr-fender-stays_p-surf-upr

Lower View fp-023c_cfd_fr-fender-stays_p-surf-lwr

Coefficients comparison

The both new 2 stays increas the front downforce. The "Stay - Louver" is less drag than "Stay - Oval Tubes".

Coefficients of the forces on the body and wheels

Coef. fp-023c Control Stay - Oval Tubes Stay - Louver Remarks
Cm 0.0781 0.0610 0.0580
Cd 0.5590 0.5618 0.5594
Cl -0.1693 -0.1863 -0.1856
Clf -0.0066 -0.0322 -0.0348
Clr -0.1627 -0.1542 -0.1509
CoP 0.9613 0.8274 0.8127
L/D -0.3028 -0.3317 -0.3318

Coefficients of the forces on the body (without wheels)

Coef. fp-023c Control Stay - Oval Tubes Stay - Louver Remarks
Cm 0.0610 0.0427 0.0397
Cd 0.4385 0.4383 0.4356
Cl -0.2099 -0.2282 -0.2277
Clf -0.0440 -0.0714 -0.0741
Clr -0.1659 -0.1568 -0.1536
CoP 0.7904 0.6872 0.6745
L/D -0.4787 -0.5207 -0.5227

Flow around the stay

The comparison figures of "U magnitude" and "Flow Vector" are shown below. The flow of "Stay - Louver" seems smoothest.

U Magnitude Comparison at Y=-520mm fp-023c_cfd_fr-fender-stays_umag-y520

Flow Vector Comparison at Y=-520mm fp-023c_cfd_fr-fender-stays_vector-y520

y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 3) 】

Front Fender Stay (Part 2)

From the comparison of the flow vector of the front fender stays, I thought a louver type stay could reduce the drag more. Therefore I designed another louver stay "Louver Stay B".

The shapes of "Louver Stay B" is shown below along with the pressure value from the simulations. ( Probably these shapes seem almost the same. / "Louver Stay" = "Stay - Louver")

fp-023c_cfd_fr-fender-louver-stay-b_p-01 fp-023c_cfd_fr-fender-louver-stay-b_p-02

Coefficients comparison

The drag and front downforce of "Louver Stay B" are less than those of "Louver Stay". But I think these differences are too small to be judged.

Coefficients of the forces on the body and wheels

Coef. Louver Stay + Fr Fender Louver C Louver Stay B + Fr Fender Louver C Difference Difference % Remarks
Cm 0.0428 0.0496 +0.0068 +15.8
Cd 0.5683 0.5622 -0.0061 -1.1
Cl -0.2051 -0.1990 +0.0061 +3.0
Clf -0.0598 -0.0499 +0.0098 +16.5
Clr -0.1453 -0.1490 -0.0037 -2.5
CoP 0.7086 0.7491 +0.0405 +4.0
L/D -0.3609 -0.3539 +0.0070 +1.9

Coefficients of the forces on the body (without wheels)

Coef. Fr Fender Louver C + Louver Stay Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0231 0.0300 +0.0068 +29.5
Cd 0.4433 0.4401 -0.0033 -0.7
Cl -0.2586 -0.2515 +0.0071 +2.7
Clf -0.1061 -0.0958 +0.0104 +9.8
Clr -0.1524 -0.1557 -0.0033 -2.2
CoP 0.5895 0.6192 +0.0297 +3.0
L/D -0.5833 -0.5716 +0.0117 +2.0

Flow around the stay

The flow of "Louver Stay B" seems smoother a little than that of "Louver Stay".

Flow Vector at Y=-520mm fp-023c_cfd_fr-fender-louver-stay-b_vt-sly520-01

U Magnitude at Y=-520mm fp-023c_cfd_fr-fender-louver-stay-b_um-sly520-01 1 13 57 fp-023c_cfd_fr-fender-louver-stay-b_um-sly520-02

Conclusion of the front fender stay simulations

At this moment, I think "Louver Stay B" is the best for the following reasons.

y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 4) 】

S-Duct B

The aero-device "S-Duct" at the nose cone ( simulated in "fp-023b - Front Aero Devices / Simulation - S-Duct : https://www.simscale.com/projects/yosukegb4/fp-023b_control/ ", the coefficients are shown below ) shifts the rear dowonforce to the front and decreases the drag a little.

Coefficients of the forces on the body and wheels

Coef. fp-023b Control S-Duct Difference Difference % Remarks
Cm 0.1330 0.1228 -0.0102 -7.7
Cd 0.5510 0.5488 -0.0022 -0.4
Cl -0.1550 -0.1579 -0.0029 -1.8
Clf 0.0555 0.0438 -0.0117 -21.0
Clr -0.2105 -0.2017 +0.0088 +4.2
CoP 1.3579 1.2776 -0.0803 -8.0
L/D -0.2813 -0.2876 -0.0063 -2.2

This "S-Duct" was just one case in the simulation of "fp-023b - Front Aero Devices". Therefore I would like to see the reactivity due to a different design of the S-Duct. I designed "S-Duct B" that inlet is 150mm forward than the original "S-Duct". The difference is shown below.

Difference between "S-Duct B" and "S-Duct (fp-023c Control)" fp-023c_cfd_s-duct-b_dimension

Coefficients comparison

The device "S-Duct B" shifts the front downforce to the rear compared with "S-Duct (fp-023c Control)". It does not meet the target to distribute the downforce more to the front.

Coefficients of the forces on the body and wheels

Coef. S-Duct (fp-023c Control) S-Duct B Difference Difference % Remarks
Cm 0.0781 0.0829 +0.0048 +6.2
Cd 0.5590 0.5599 +0.0009 +0.2
Cl -0.1693 -0.1698 -0.0006 -0.3
Clf -0.0066 -0.0020 +0.0045 +68.9
Clr -0.1627 -0.1678 -0.0051 -3.1
CoP 0.9613 0.9880 +0.0267 +2.7
L/D -0.3028 -0.3034 -0.0006 -0.2

Coefficients of the forces on the body (without wheels)

Coef. S-Duct (fp-023c Control) S-Duct B Difference Difference % Remarks
Cm 0.0610 0.0657 +0.0047 +7.8
Cd 0.4385 0.4389 +0.0004 +0.1
Cl -0.2099 -0.2101 -0.0002 -0.1
Clf -0.0440 -0.0394 +0.0046 +10.5
Clr -0.1659 -0.1708 -0.0049 -2.9
CoP 0.7904 0.8126 +0.0222 +2.2
L/D -0.4787 -0.4788 -0.0001 -0.0

Pressure and U Magnitude comparisons

Surface Pressure fp-023c_s-duct-b_p-01 fp-023c_s-duct-b_p-02

Pressure at Y=0mm fp-023c_s-duct-b_p-y000-01

U Magnitude at Y=0mm fp-023c_s-duct-b_u-y000-01

y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 5) 】

Front Fender Louver C + Louver Stay B

The combination of "Front Fender Louver C" and "Louver Stay B" was simulated.

Coefficients comparison

These increase the downforce without much increasing the drag and distribute the downforce to the front more.

Coefficients of the forces on the body and wheels

Coef. fp-023c Control Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0781 0.0496 -0.0285 -36.5
Cd 0.5590 0.5622 +0.0032 +0.6
Cl -0.1693 -0.1990 -0.0297 -17.5
Clf -0.0066 -0.0499 -0.0434 -662.1
Clr -0.1627 -0.1490 +0.0137 +8.4
CoP 0.9613 0.7491 -0.2122 -21.2
L/D -0.3028 -0.3539 -0.0511 -16.9

Coefficients of the forces on the body (without wheels)

Coef. fp-023c Control Fr Fender Louver C + Louver Stay B Difference Difference % Remarks
Cm 0.0610 0.0300 -0.0310 -50.8
Cd 0.4385 0.4401 +0.0016 +0.4
Cl -0.2099 -0.2515 -0.0416 -19.8
Clf -0.0440 -0.0958 -0.0518 -117.7
Clr -0.1659 -0.1557 +0.0102 +6.1
CoP 0.7904 0.6192 -0.1712 -17.1
L/D -0.4787 -0.5716 -0.0929 -19.4
y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 6) 】

Ride Height Comparison

The aero-devices set of the simulations for the ride heights comparison is "fp023c Control + Fr Fender Louver C + Louver Stay B". The value of "Reference area value [m²]" are the same "0.645" for the all ride height simulations.

Coefficients comparison

The positive rake angle and the lower ride height make more downforce as same as other general formula cars. And the horizontal attitudes and the lower ride height reduce the drag.

Coefficients of the forces on the body and wheels

Coef. RH110-110 RH90-110 RH90-90 Remarks
Cm 0.0496 0.0221 0.0503
Cd 0.5622 0.5641 0.5562
Cl -0.1990 -0.2544 -0.2487
Clf -0.0499 -0.1051 -0.0741
Clr -0.1490 -0.1493 -0.1746
CoP 0.7491 0.5870 0.7022
L/D -0.3539 -0.4509 -0.4472

Coefficients of the forces on the body (without wheels)

Coef. RH110-110 RH90-110 RH90-90 Remarks
Cm 0.0300 0.0036 0.0309
Cd 0.4401 0.4380 0.4362
Cl -0.2515 -0.3013 -0.2923
Clf -0.0958 -0.1471 -0.1152
Clr -0.1557 -0.1542 -0.1771
CoP 0.6192 0.5118 0.6058
L/D -0.5716 -0.6880 -0.6701

Pressure and U Magnitude Comparisons

These seem almost the same below, but the differences seen around the edges of the reference plane, on the bottom surfaces of the front wing, between the front fender louver and the front wheel and so on.

Pressure on the body and wheels - Bottom View fp-023c_cfd_rh-comparison_p-surf_bottom-view

U Magnitude at Y=-1mm fp-023c_cfd_rh-comparison_u-mag_y0001

U Magnitude at Y=-100mm fp-023c_cfd_rh-comparison_u-mag_y0100

U Magnitude at Y=-200mm fp-023c_cfd_rh-comparison_u-mag_y0200

U Magnitude at Y=-300mm fp-023c_cfd_rh-comparison_u-mag_y0300

U Magnitude at Y=-400mm fp-023c_cfd_rh-comparison_u-mag_y0400

U Magnitude at Y=-500mm fp-023c_cfd_rh-comparison_u-mag_y0500

U Magnitude at Y=-600mm fp-023c_cfd_rh-comparison_u-mag_y0600

U Magnitude at Y=-700mm fp-023c_cfd_rh-comparison_u-mag_y0700

U Magnitude at Y=-800mm fp-023c_cfd_rh-comparison_u-mag_y0800

U Magnitude at Y=-900mm fp-023c_cfd_rh-comparison_u-mag_y0900

U Magnitude at Y=-1000mm fp-023c_cfd_rh-comparison_u-mag_y1000

U Magnitude at Y=-1100mm fp-023c_cfd_rh-comparison_u-mag_y1100

U Magnitude at Y=-1200mm fp-023c_cfd_rh-comparison_u-mag_y1200

y-yosuke commented 8 years ago

【 fp-023c - Summary of the Results (Part 7) 】

Conclusion

As in the results of "Front Fender Louver C + Louver Stay B" and "Ride Height Comparison", I achieved the goal to distribute the front and rear downforces of the body to be about 60-65%. ( Clf : Clr = 40-35 : 60-65 )

As a next step, I would like to develop the rear aero-devices as shown below and so on.