Comparison With Span Efficiency Factor
It is frequently assumed that Oswald efficiency number is the same as the span efficiency factor which appears in Lifting-line theory, and in fact the same symbol e is typically used for both. But this assumes that the profile drag coefficient is independent of, which is certainly not true in general. Assuming that the profile drag itself has a constant+quadratic dependence on, an alternative drag coefficient breakdown can be given by
where
-
is the constant part of the profile drag coefficient, is the quadratic part of the profile drag coefficient, is the wing span efficiency factor from inviscid theory, such as Lifting-line theory
Equating the two expressions gives the relation between the Oswald efficiency number e0 and the lifting-line span efficiency e.
For the typical situation, we have .
Read more about this topic: Oswald Efficiency Number
Famous quotes containing the words comparison with, comparison, span, efficiency and/or factor:
“I have travelled a good deal in Concord; and everywhere, in shops, and offices, and fields, the inhabitants have appeared to me to be doing penance in a thousand remarkable ways.... The twelve labors of Hercules were trifling in comparison with those which my neighbors have undertaken; for they were only twelve, and had an end; but I could never see that these men slew or captured any monster or finished any labor.”
—Henry David Thoreau (1817–1862)
“I have travelled a good deal in Concord; and everywhere, in shops, and offices, and fields, the inhabitants have appeared to me to be doing penance in a thousand remarkable ways.... The twelve labors of Hercules were trifling in comparison with those which my neighbors have undertaken; for they were only twelve, and had an end; but I could never see that these men slew or captured any monster or finished any labor.”
—Henry David Thoreau (1817–1862)
“School-days, I believe, are the unhappiest in the whole span of human existence. They are full of dull, unintelligible tasks, new and unpleasant ordinances, brutal violations of common sense and common decency. It doesn’t take a reasonably bright boy long to discover that most of what is rammed into him is nonsense, and that no one really cares very much whether he learns it or not.”
—H.L. (Henry Lewis)
“I’ll take fifty percent efficiency to get one hundred percent loyalty.”
—Samuel Goldwyn (1882–1974)
“You factor in racism as a reality and you keep moving.”
—Jewell Jackson McCabe (b. 1945)