ASSPIN Users' Manual - CAFE Foundation

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ObserverCoordinates.The acoustic observers are assumed to translate with the aircraft. Their coordinatesare expressed in meters and are specified by the user with respect to the aircraft fixedreference frame.Input File StructureThe order and format of the user supplied input file is discussed in this subsection.Both SRP and CRP predictions are considered. Examples involving both cases appearin the next section.SRPPredictions.1. 80 character identifier - FORMAT(IX,AS0).2. NAMELIST PHYSCAL - NCRP = 0 for SRP Predictions.3. NAMELIST GRID.4. Blade coordinates and surface pressure data.4a. NEPTS, NQPTS, NTPTS - FORMAT(IX, 3110).4b. Relative chord grid - FORMAT(IX, E15.7).Q1 = 0.0QNQPTS : 1.04c. ,72,CH, AZ, _FORMAT(IX, 5m5.7).YL(Q1), yu(Q1), PL(Q1), pu(Qi)- FORMAT(IX, 4E15.7).YL (QNQPTS)' Yu(QNo. PTS )' PL ( QNQeTS )' Pu(QNQPTS )- FORMAT(IX, 4E15.7).The quantities PL and Pu refer to steady blade pressure. If the blade loads areunsteady, then <strong>ASSPIN</strong> does not use PL and Pu" However, properly formattednumbers must appear in these locations.Item 4c. is repeated for each of the NEPTS airfoil sections.4d. Time point grid for unsteady surface pressure - FORMAT(IX, 5E13.6).READ(5)(T(K), K = 1,NTPTS)3O
T(1) = 0.0, ..., T(NTPTS) = 27r.If STEADY = TRUE, then 4d. is omitted.4e. Unsteady surfacepressure- FORMAT(IX, 5E13.6).DO K = 1,NTPTSDO I = 1,NEPTSREAD(5)(pc (I,J,K), J = 1,NQPTS)READ(5)(pu(I,J,I(), J = 1,NQPTS)If STEADY = TRUE, then 4e. is omitted.5. Observercoordinates - Unformatted.READ(5,*)((£(I,J),a = 1,3), I = 1,NOBS)is the a-th Cartesian component, with respectto the aircraft fixedfi'ame, of the I-th observer.CRPPredictions.1. 80 character identifier - FORMAT(A80).2. NAMELIST PHYSCAL for forward propeller - NCRP = 1.3. NAMELIST GRID for forward propeller.4. Blade coordinates and surface pressure data for forward propeller.See format and instructions for SRP predictions.5. Observer coordinates.See format and instructions for SRP predictions.The origin of the aircraft fixed fi'ame is assumed to be at the hub centerof the forward propeller (see Figure 6).6. NAMELIST PHYSCAL for aft propeller - NCRP = 2.NOBS and NB are the same for both propellers. RPM for the aft propeller must bethe negative of RPM for the forward propeller.7. NAMELIST GRID for aft propeller.NT must be tile same for both propellers.31
Page 2 and 3: _I7_--- k r_ - .___._- z_ l
Page 5 and 6: CONTENTSLIST OF FIGURES ...........
Page 7 and 8: SUMMARYThis document describes the
Page 9 and 10: nb'._7CRPcounter-rotationpropellerC
Page 11 and 12: 0 angle between _ and 77)" blade su
Page 13 and 14: surface integrals over the moving b
Page 15 and 16: with f = 0, k > 0 defining an open
Page 17 and 18: frame at all times. The angle betwe
Page 19 and 20: whereA21(r) = - SillCOr cos cor 0 ,
Page 21 and 22: 2_A -- C027?x,co2'z sin + (d - 3)co
Page 23 and 24: the approximation of g in the neigh
Page 25 and 26: (a) Blade DiscretizationN1SUB N1SUP
Page 27 and 28: computer execution time by approxim
Page 29 and 30: the user is interested in CRP predi
Page 31 and 32: appear on the left hand side of the
Page 33 and 34: Blade Geometry and Surface Pressure
Page 35: Table 3. Geometry and Loading Input
Page 39 and 40: set to their default values(seeTabl
Page 41 and 42: 2500145io2000fllo. 1500n-THICKNESS
Page 43 and 44: 175014513.1250¢1:-'-, 750O_COIJJn,
Page 45 and 46: 6. Dunn, M. H. and Tarkenton, G. M.
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