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The aerodynamic characteristics of a distributed electric propulsion system were investigated through wind tunnel tests, with a focus on the coupling mechanism between propeller slipstream and wings and the influence of propeller installation positions on the lift characteristics of the system. The test results indicate that the distributed electric propulsion system significantly increases the maximum lift coefficient of the wing and delays stall, with the highest lift coefficient increasing by 63%. The axial and vertical positions of the propeller have a significant effect on aerodynamic performance. Maximum lift increment is obtained when the installation position ratio is close to 1. The distributed electric propulsion systems can significantly enhance lift and suppress flow separation, which provides an efficient lift enhancement method for short take-off and landing aircraft.

The aerodynamic performance of distributed propulsion aircraft is significantly influenced by the propeller layout. Identifying the optimal relative position between propellers and wings is a critical task during the conceptual design phase of aircraft development. This study took the Tecnam P2006T aircraft as a reference model and utilized the vortex lattice method combined with a back propagation (BP) neural network to rapidly calculate and predict the lift coefficient, the drag coefficient, and the lift-to-drag ratio under different propeller layout configurations. The optimal propeller layout position is determined from the perspective of minimizing the takeoff distance and maximizing overall aerodynamic performance. Compared to the aerodynamic performance of the original propeller layout, the optimized configuration significantly improves the propeller slipstream effect, improves the lift coefficient and lift-to-drag ratio, and reduces the ground roll takeoff distance. This method provides a practical solution for the rapid optimization of leading-edge propeller layouts for distributed propulsion aircraft.

Due to global warming concerns, the Aviation industry is trying to reduce its carbon footprint. Electric propulsion (EP) is one way of doing this, where the power is obtained from electrical sources. The concept of distributed electric propulsion (DEP) is in the focus now. NASA’s X-57 Maxwell, a high winged, all-electric experimental aircraft, uses this concept. The present work aims at developing a CFD model (ANSYS Fluent) to evaluate aerodynamic performance of two configurations of NASA’s X-57 aircraft wing; (i) wing and nacelle (clean wing) and (ii) wing, nacelle and one electric propeller under cruise condition; and compare it with the results of wind tunnel experiment performed by NASA/Armstrong X-57 research program. Parameters like lift, drag and pressure coefficients (CL, CD, CP) are compared for both cases. A good match is observed for CL, CD and CP, thus validating the model. The unsteady RANS solver is very efficient in capturing the effects of propeller slipstream on the wing. After validation, this model is further used to simulate aerodynamic performance of a wing with multi-propeller (DEP) configuration.

The structural design of the rudder, traditionally based on quasisteady loads generated during worst manoeuvres, should account for load fluctuations associated with the interaction with the wake of the propeller in order to comply with the more stringent requirements on ship vibration and noise pollution. In this context, the present work analyses the dynamic response of a marine rudder located in the wake of the INSEAN E779A propeller by the one-way fluid–structure interaction approach. The time-dependent pressure distribution on the rudder, obtained through detached eddy simulation, is used to evaluate the pressure field that is the input for a structural solver to determine the resulting deformations and stresses. The computations consider the propeller at moderate loading, and rudder deflection angles at neutral and $4^{\\circ }$. The analysis discusses the different contribution of the tip and hub vortex of the propeller on the static and vibratory response of the rudder in the two configurations.

Increased high-lift capabilities due to propeller slipstream, i.e. slipstream deflection, is seen to be one of the main benefits of distributed propulsion, as it may lead to a reduction in the main wing size and thus to reduced drag in cruise flight and/or reduced system weight and complexity. The presented work assesses the potential of distributed propulsion on the high-lift capabilities of a novel transport aircraft design from an aerodynamic point of view. The assessment is based on a regional propeller-driven transport aircraft designed within the European IMOTHEP project. Based on the initial aircraft design, a sensitivity study on the number of propellers and propeller positions with regards to the maximum lift coefficient under take-off conditions has been performed. Moreover, adjustments to the nacelle design and the propulsor integration have been investigated. The study indicates significant increases in the maximum effective lift coefficient in take-off of up to +42% due to slipstream deflection. The increase is thereby strongly dependent on the number of propellers and the propeller positions.

The aerodynamic characteristics of turboprop aircraft are greatly affected by the running propellers. In this paper, propeller slipstream effects on the static lateral-directional stability characteristics of a typical twin-engine turboprop aircraft with clockwise rotating propellers were investigated through unsteady computational fluid dynamics (CFD) simulations and wind tunnel experiments. The propeller slipstream led to a significant decrease in the lateral static stability contribution of the wing-body-nacelle (WBN), and the most affected wing sections were located near the left boundary of the port propeller slipstream region. Moreover, the influence of the propeller slipstream on the lateral static stability contribution of the vertical tail plane (VTP) significantly altered the rolling moment curve slope of the entire airframe. Due to the effects of the propeller slipstream on the local dynamic pressure and therefore the effectiveness of the VTP, the aircraft showed significantly different directional static stability behaviors between the positive and negative sideslip conditions. Furthermore, it was found that the configurations with clockwise rotating propellers readily experience dramatic losses in directional static stability at large negative sideslip angles.

Ships sailing in harbour environments will experience four-quadrant manoeuvres, based on the direction of ship velocity and propeller rate. A better understanding of ship hydrodynamics in such manoeuvres will contribute to the navigation safety. Aimed at ships equipped with a conventional single propeller and single rudder, the hydrodynamic performance of a rudder with the engine ahead and astern is studied. The KP505 propeller and NACA 0018 semi-balanced rudder (from the KCS benchmark ship) are selected for numerical studies for extended experimental data published. After validating numerical methods with open-water test data for the single propeller and the single rudder, CFD simulations based on RANS methods are conducted for different advance ratios ahead and astern, with rudder deflections ranging from 0 to 15 degrees. To understand propeller impact on lift and drag forces of the rudder in different working conditions, inflow to the rudder in propeller slipstreams are analysed by extracting the flow field data in different profiles along the rudder span. Streamlines around the rudder and pressure distributions on the rudder surfaces, along with the turbulent kinematic energy distributions and the vortex structures visualised by Q-criterion, are compared to reveal propeller-rudder interaction mechanisms in ahead and astern conditions. The study shows that the propeller rotation mode has a significant impact on rudder inflow patterns, and induced rudder forces change in different trends with propeller loading variations.

This research investigates the propeller - stator configuration containing eight bladed transonic rotor and a stator with ten blades as Swirl Recovery Vanes (SRVs) in order to improve the efficiency of propeller propulsion systems. By incorporating SRVs behind the propeller, the study aims to decrease rotational kinetic energy losses, ultimately enhancing aerodynamic performance. The primary goal is to reduce swirl, resulting in a 4.46% increase in power coefficient. The approach entails employing potential-based design methodologies in conjunction with time-accurate Reynolds-averaged Navier-Stokes (RANS) simulations. The simulations were validated through comparisons between the numerical and analytical slipstream data. Further enhancement of additional thrust of 23N and improvement in the efficiency of the propeller by 3.47% during cruise phase is achieved. Also, the results indicated a potential increase in the overall propulsive efficiency of the propeller – SRV combination to an extent of up to 3.46%. These improvements are achieved by varying the pitch distribution of the SRVs to enhance swirl recovery. Adjusting the pitch has demonstrated an increase in these gains by enhancing the swirl recovery of the rotor. The flow in the propeller slipstream leads to the emergence of unsteady phenomenon on the vanes. Design modifications to the swirl recovery vanes are deemed necessary for achieving further improvement in these configurations.

In this work, the flow surrounding the train was obtained using a detached eddy simulation (DES) for slipstream analysis. Two different streamlined nose lengths were investigated: a short nose (4 m) and a long nose (9 m). The time-average slipstream velocity and the time-average slipstream pressure along the car bodies were compared and explained in detail. In addition to the time-averaged values, the maximum velocities and the pressure peak-to-peak values around the two trains were analyzed. The result showed that the nose length affected the slipstream velocity along the entire train length at the lower and upper regions of the side of the train. However, no significant effect was recognized at the middle height of the train along its length, except in the nose region. Moreover, within the train’s side regions ( y =2.0–2.5 m and z =2–4 m) and ( y =2.5–3.5 m and z =0.2–0.7 m), the ratio of slipstream velocity U max between the short and long nose trains was notably higher. This occurrence also manifested at the train’s upper section, specifically where y =0–2.5 m and z =4.2–5.0 m. Similarly, regarding the ratio of maximum pressure peak-to-peak values Cp – p max , significant regions were observed at the train’s side ( y =1.8–2.6 m and z =1–4 m) and above the train ( y =0–2 m and z =3.9–4.8 m).