THE UNIVERSITY of ADELAIDE SUB CRUCE LUMER Semester 2, 2014 104414 Applied Aerodynamics MECH ENG 3101, 7068 Official Reading Time: 10 mins Writing Time: 180 mins Total Duration: 190 mins Parts A B Questions Answer all questions Answer all questions Time 110 mins (Recommended) 70 mins (Recommended) 125 Total Instructions for Candidates . This is an Open Book examination (refer to Permitted Materials). · Answer all questions. · Answer Part A and Part B in separate books and label each book. . Examination materials must not be removed from the examination room. . The marks for each question are indicated. · Begin each answer on a new page in the answer book. . Show all calculations and assumptions in the answer book. · Write your name and Student ID number on all loose diagrams/papers. Permitted Materials · Two Pink books. · Notes and textbooks permitted. · Calculator without remote communications capability permitted · Graphics calculator permitted · English language dictionaries are permitted. Marks 75 marks 50 marks DO NOT COMMENCE WRITING UNTIL INSTRUCTED TO DO SO
Course ID: MECH ENG 104414 Page 2 of 11 Part A (Total 75 marks) Answer all these questions in an answer book. Clearly indicate "Part A" on the front of the answer book. Useful graphs are given at the end of this question paper. Q1. [25 marks] a) A smooth plastic ball of 50 mm diameter is dropped from an aircraft at low altitude. The density of the ball is Pball = 800 kg/m3. Find the terminal velocity of this ball as it falls towards the ground. Figure 1 below should be of assistance. A graphical solution is acceptable. State all assumptions. [16 marks] Note that Figure 1 is repeated on the last page of this question paper. This can be removed and placed in your exam booklet if required. Please write your name and Student ID number on this page if you do this. The air properties are: Pair = 1.2 kg/m3 and uair = 1.8 x 10-5 N.sm-2. CD 0.6 0.5 Smooth 0.4 0.3 Rough 0.2 0.1 0.0 2 104 4 6 8 105 2 4 6 8 106 Re Figure 1. Cp versus Re (based on diameter) for rough and smooth spheres. b) If a light-weight streamlined tail is added to the smooth sphere, what is the potential increase in the terminal velocity of the ball. [6 marks] c) In Figure 1 (above) there are two Cp curves; one for rough spheres and one for smooth spheres. Briefly explain why these curves are different. [3 marks] PLEASE SEE NEXT PAGE
Course ID: MECH ENG 104414 Page 3 of 11 Q2. [25 marks] A 1969 Formula 1 car, similar to the car shown in Figure 2, car has a rectangular rear wing mounted high above its rear wheels. The wing measures 1.5 m span, 0.5 m chord and it has an angle of attack of 8.2 degrees. The wing has small end plates which are sufficient to ensure two-dimensional flow over the