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Analysis of the effects of wall perforations on the performance of a vehicle in a tube

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21 appropriate relations for the drag disc are 2 i - Vd. 2.4 2.12 2.15 For the inflow region ahead of the actuator disc…
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22 or, in normalized form, 2.32 Equations 2.30, 2.31 and 2.32 are not all independent, hence one more equation is needed -…
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23 P-"A a.. .3 _ 2 1 ( XL - - - - - - 2~-i - (2u3 -i)e. - 4 sinh (-?-..'L) J( ~L J2 r: + ~2U.-t) e - (…
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24 where Thus the entire flow field is specified for the case of matched internal propulsion. The drag, and consequently the…
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25 Between the actuator and drag discs, (from 4 to 1) the pressure will increase causing outflow and a decrease in velocity.…
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. / 26 and integration from the drag disc (X = 0) forward yields sln (-?\.X + C.3) 2.41 where At X = L, U = U3 and eq. 2.…
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which is of course, equal to the thrust, P a - P 3 • The critical length is given by 2.45 Equations 2.12 and 2.15 still…
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which then permits specifying j3. Then from the definition of t/ and an assumed value of U d , P 1 - P a can be…
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therefore Pl also equals Pa which further requires that u1 = u 4 = u • This is possible under two conditions. One is the…
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30 pressure behind the actuator disc (the thrust) is equal to the drop in pressure to atmospheric behind the drag disc (the…
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31 3. EXPERIMENTAL APPARATUS AND PROCEDURE Experiments were conducted for two purposes: first, to deter- mine the…
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connected to one side of a U-tube water manometer, give the pressure difference across the tube wall directly. 32 The rotary…
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33 consecutively, to 1/4, 7/16 and S/S inches and the entire procedure repeated. 3.1.3. Data Reduction. The tube axial…
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34 was constructed for the purpose of extending the range of tests and for testing the drag disc in a porous tube. This…
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35 rates was obtained by adjusting the control valve and new readings were made. Discs of different porosities were then…
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36 4. DISCUSSION OF RESULTS Solutions to the equations of motion governing the flow field induced by a vehicle traveling…
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37 All of the data points for inflow appear to lie on the same straight line through the origin corresponding to a flow…
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38 The viscous flow solution is for a tube-wall fricition factor of C~= .01 and a 2.5 per cent wall porosity. All solutions…
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39 evident even for wall porosities as low as 1 or 2.5 per cent. The drag of the disc, given by eq. 2.17, is presented in…
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40 U d '2. .5 and of U = .5 for Uci <'.5 is maintained. The effect of viscosity is to bring the flow to rest…
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41 only about 20 tube radii with very good correlation between theory and experiment. A 1/4" aluminum disc with 1/4…
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presented in Fig. 20 show the same general trend as the experimental results shown in Fig. 21, which has been reproduced from…
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43 constant area, cylindrical fairing 14• An actuator disc operating in a finite length constant area fairing produces a low…
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blockage. Frictional drag on the vehicle is not included. Under conditions of level motion, the thrust on the vehicle must…
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per cent wall porosity but with a further decreased length of disturbed flow ahead of the drag disc. Behind the actuator disc…
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