An airfoil profile to be used on a wind turbine blade is testedin a wind tunnel. The prototype (full-scale) airfoil section has achord length of 2m and moves at 50 m/s relative to the wind, thewind tunnel model has a chord length of 0.4m. The temperature forthe model test is the same as for prototype operation.
(a) What criterion should be used to obtain dynamic similarityin the experiment? (Write out the criterion in an equation.) (b)What velocity should the wind tunnel be operated at to have dynamicsimilarity for the scale model? (assuming tests at atmosphericpressure.) (c) The wind tunnel available for this test can only beoperated at 100 m/s, but it can also be pressurized. What pressureshould be used in the wind tunnel to have dynamic similarity?(Assume the air behaves like an ideal gas.)
