The order of fulfilling laboratory work.
In this laboratory work the drained model of wing and device for it retaining in working part of wind tunnel, what descriptions are used in laboratory work of "Research of distribution of pressure along the profile of wing".
For creation of effect of sweep back angle basis of holding device is set on a horizontal underlayment in test part of a wind tunnel and revolve for the change the angle between the front edge of wing and axis of wind tunnel (fig.6).
1.
To set the model of wing in test section of the wind tunnel so that
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To set the set angle of attack of wing (the value of angle of attack
and range of these values are set by teachers). To start wind tunnel
to conduct measuring and fill a table (table 1)
Coefficients of pressure are in the drainage points of model of wing
table 1
і |
1 |
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3 |
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срі |
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i is a number of the drainage hole; is a readings of the micromanometer connected with the drainage hole; is a readings of the micromanometer connected with the entrance crossing of nozzle of wind tunnel; μ is a mid-coefficient of the field of dynamic pressures of test section of the wind tunnel; срі is a coefficient of pressure in a given drainage point. The coefficient of pressure is counted up by a formula
The detailed explanation of sense of the indicated quantities is given in the laboratory work "Research of distribution of pressure driven to laboratory work along the profile of wing".
In a table 1 to find ср min and, using the method of Hrystianovich, to count up the value of Мcr.
To fill analogical tables and produce corresponding actions for the row of values of the anglts of attack, indicated by a teacher.
2.
To set the model of wing in wind tunnel so that a angle
equaled one of values indicated by a teacher.
(To install a model on the set sweep back angle, using marking on the horizontal holder of test section of wind tunnel). Set to one of values of angles of attack, that was used in a point 1. To count up the corresponding value of angle of setting of wing on the limb of the holder.
To do measurements and fill a table like a table 1. Using the method of Hrystianovichaа to count up the value of Мcr.
To repeat the actions of this point for the row of value of angles of attack of indicated before.
To repeat all previous actions of this point for the row of values of the sweepback angle, indicated by a teacher.
3. On results points 1, 2 to build the row of charts of dependence of Мcr. from the angle of attack, using the sweep back angle as parameter.
