Automotive Engineering Exam 2 with correct 2024 answers
1. Skin friction i. Viscous drag in the bound- ary layer ii. Friction of the fluid (air) against the object's "skin" (auto body) 2. Form Drag i. Caused by pressure differ- ential in front of/behind ve- hicle as viewed by the air stream. ii. Keys for reducing: con- tinuous streamlines, avoiding flow separation. 3. Contributors to drag Forebody, Afterbody, Under- body, Skin friction, wheels and wheel wells, drip rails, window recesses, external mirrors, etc. 4. Pressure Distribution on a vehicle Figure 4.6 and 4.7 5. Directional Dependence Sideforce can be significant. Less so on passenger cars but pronounced effects on trucks and tractor trailers. The separation region causes a pressure difference (i.e. form drag) which is why they're so easily blown over. 6. Mechanisms of Rolling Resistance a. Energy loss due to sidewall deflection b. Energy loss due to tread element deflection c. Scrubbing in the contact patch d. Trie slip in longitudinal and lateral
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- Automotive Mechanic And Electronic
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