scholarly journals Preliminary Determination of Propeller Aerodynamic Characteristics for Small Aeroplanes

10.14311/558 ◽  
2004 ◽  
Vol 44 (2) ◽  
Author(s):  
S. Slavík
Keyword(s):  
Aerodynamic Characteristics ◽  
Propeller Blade ◽  
Analytical Functions ◽  
Advance Ratio ◽  
Propeller Blades ◽  
Lift And Drag ◽  
S Model ◽  
Integral Decomposition ◽  
Preliminary Determination

This paper deals with preliminary determination of propeller thrust and power coefficients depending on the advance ratio by means of some representative geometric parameters of the blade at a specific radius: propeller blade chord and blade angle setting at 70 % of the top radius, airfoil thickness at the radius near the tip and the position of the maximum blade width. A rough estimation of the non-linear influence of propeller blades number is included.The published method is based on Lock`s model of the characteristic section and the Bull-Bennett lift and drag propeller blade curves. Lock`s integral decomposition factors and the loss factor were modified by the evolution of the experimental propeller characteristics. The numerical-obtained factors were smoothed and expressed in the form of analytical functions depending on the geometric propeller blade parameters and the advance ratio.

Coupled Engine Torsional and Propeller Flexural Vibrations

1945 ◽  
Vol 153 (1) ◽  
pp. 41-58 ◽  
Author(s):  
J. Morris
Keyword(s):  
Basic Assumption ◽  
Early Stage ◽  
Torsional Vibrations ◽  
Propeller Blade ◽  
Blade Section ◽  
Flexural Vibrations ◽  
Propeller Blades ◽  
Engine Crankshaft ◽  
Theoretical Results

In the initial treatment of resonant torsional vibration in engine crankshaft propeller systems, the basic assumption was made that for practical purposes a propeller could be regarded as a rigid pulley in the plane of rotation. At an early stage, however, it became evident that theoretical results ensuing from the rigid pulley hypothesis could not explain certain engine-propeller failures, and thus it came to be realized that the flexibility of the propeller blades must have an important influence in coupled crankshaft-propeller vibrations. In this paper an analytical method is given for the determination of coupled engine torsional and propeller flexural vibrations, in which account is taken of blade section, blade twist, hub moment of inertia, pitch setting angle, and speed of rotation. The propeller blade is divided chordwise into six portions which are regarded as having their masses concentrated at their centres of gravity, while account is taken, so far as is possible, of the actual elastic properties of the blade. In the case of an aircraft propeller, the problem is simplified in that the mass axis is practically straight and coincident with the flexural axis, so that flexural and torsional vibrations of the blade itself are not coupled. The theory has been applied to a three-blade propeller used on two different engines, in both of which agreement between the calculated critical speeds and those observed experimentally on the cable hangar was found to be satisfactory. Moreover, the calculated fixed root frequencies for the fundamental and six overtones accorded very closely with the corresponding values evidenced on a -model of the blade by bowing and calibrated oscillator tests.

Computational Fluid Dynamic Analysis of the Flow Around a Propeller Blade of Multirotor Unmanned Aerodynamic Vehicle

2021 ◽  
Author(s):  
Victor H. Martinez ◽  
Kiran Bhaganagar
Keyword(s):  
Fluid Dynamic ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Propeller Blade ◽  
Computational Fluid Dynamic Analysis ◽  
Thrust Coefficient ◽  
Emergency Rescue ◽  
Propeller Blades

Abstract Multirotor Unmanned Aerodynamic Vehicles (MUAV) have been a high interest topic in the aerodynamic community for its many applications, such as, logistics, emergency rescue, agriculture data collection, and environmental sensing to name a few. MUAV propeller blades create a highly complex turbulent fluid flow around the body and the environment around it. The flow physics generated from the rotation of the propeller blades were studied in this paper along with the analysis of aerodynamic characteristics. A Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) analysis of a propellor blade from a MUAV has been performed to quantify the aerodynamic effects. For this purpose, the verification and validation of the commercially available CFD solver COMSOL Multiphysics v5.5 was performed using the NACA 0012 airfoil which is one of the most highly studied of the NACA family. With this validation it created confidence on the results for simulating a MUAV propeller and evaluate the aerodynamic characteristics of thrust coefficient (KT), power coefficient (KP), and Efficiency (η). These characteristics were compared against experimental data and results showed to have a similar trend. This showed that the CFD solver is capable of solving the aerodynamic characteristics of any propeller blade geometry.

scholarly journals Computational Study Of Curved Underbody Diffusers

2019 ◽  
Vol 128 ◽  
pp. 10002
Author(s):  
Angel Huminic ◽  
Gabriela Huminic
Keyword(s):  
Computational Study ◽  
Aerodynamic Characteristics ◽  
Passenger Car ◽  
Lift And Drag ◽  
Underbody Diffuser ◽  
Ahmed Body

This paper presents new results concerning the aerodynamics of the Ahmed body fitted with a non-flat underbody diffuser. As in previous investigations performed, the angle and the length of the diffuser are the parameters systematically varied within ranges relevant for a hatchback passenger car. Coefficients of lift and drag are compared with the values obtained for the flat underbody diffuser, and the results reveal significant improvements concerning aerodynamic characteristics of body.

Numerical study of geometric morphing wings of the 1303 UCAV

2021 ◽  
pp. 1-17
Author(s):  
B. Nugroho ◽  
J. Brett ◽  
B.T. Bleckly ◽  
R.C. Chin
Keyword(s):  
Flight Control ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Morphing Wing ◽  
Rolling Moment ◽  
Wide Range ◽  
Morphing Wings ◽  
Wing Geometry ◽  
Lift And Drag ◽  
Wing Morphing

ABSTRACT Unmanned Combat Aerial Vehicles (UCAVs) are believed by many to be the future of aerial strike/reconnaissance capability. This belief led to the design of the UCAV 1303 by Boeing Phantom Works and the US Airforce Lab in the late 1990s. Because UCAV 1303 is expected to take on a wide range of mission roles that are risky for human pilots, it needs to be highly adaptable. Geometric morphing can provide such adaptability and allow the UCAV 1303 to optimise its physical feature mid-flight to increase the lift-to-drag ratio, manoeuvrability, cruise distance, flight control, etc. This capability is extremely beneficial since it will enable the UCAV to reconcile conflicting mission requirements (e.g. loiter and dash within the same mission). In this study, we conduct several modifications to the wing geometry of UCAV 1303 via Computational Fluid Dynamics (CFD) to analyse its aerodynamic characteristics produced by a range of different wing geometric morphs. Here we look into two specific geometric morphing wings: linear twists on one of the wings and linear twists at both wings (wash-in and washout). A baseline CFD of the UCAV 1303 without any wing morphing is validated against published wind tunnel data, before proceeding to simulate morphing wing configurations. The results show that geometric morphing wing influences the UCAV-1303 aerodynamic characteristics significantly, improving the coefficient of lift and drag, pitching moment and rolling moment.

Determination of Underwater Plate Dynamics Using Laser Beams

1974 ◽  
Vol 96 (3) ◽  
pp. 722-728
Author(s):  
Rudolph E. Croteau ◽  
Herman E. Sheets
Keyword(s):  
Near Field ◽  
Surface Displacement ◽  
Coupled System ◽  
Green Laser ◽  
Testing Facility ◽  
Acoustic Testing ◽  
Propeller Blades ◽  
The Relationship ◽  
Made In

Underwater plate vibration and its associated noise are of interest for the analysis of ship structures, propeller blades, and other areas of underwater acoustics. In order to analyze the relationship between a plate vibrating underwater and the acoustic pressure in the near-field, optical interferometric holography, using a blue-green laser beam, was used to determine surface displacement for the vibrating plate, which was excited through a fluid-coupled system. Acoustic measurements of the same source were made in a water tower concurrently with the holography and later at a precision acoustic testing facility. This method permits prediction of underwater plate modal frequencies and shapes with high accuracy.

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