Aerodynamic Optimization of Quadrotor Blades Operating in the Martian Atmosphere

Unmanned Aircraft Systems (UAS) are state of the art in the aerospace industry and are involved in many operations. While initially developed for military purposes, commercial applications with small-scale UAS, such as multicopters, are today frequent. Accurate engineering tools are required to assess the performance of these vehicles and optimize power consumption. Thrust and power curves of rotors used by small-scale UAS are essential to design efficient systems. The lack of experimental data and accurate prediction models to evaluate rotor coefficients over the UAS flight envelope are two substantial limitations in UAS science. In addition, Reynolds numbers based on the chord for small-scale rotors at usual rotation rates are usually smaller than 100,000 resulting in degraded performance. In this paper, we describe two in-house Reduced Order Models (ROM's), namely a Blade Element Momentum (BEM) code and a Non-Linear Lifting Line Theory approach combined with Free Vortex Wake (NLLT-FVW) code. We verify these models with three-dimensional Computational Fluid Dynamics (CFD) simulations, and we validate them with existing experimental data for blades in low Reynolds conditions. We also use two-dimensional CFD simulations to generate the aerodynamic database for the reduced-order models. 

Numerical and experimental validation and comparison of reduced order models for small scale rotor hovering performance prediction

Recent developments in agriculture mechanization have generated significant challenges towards sustainable approaches to reduce the environmental footprint and improve food quality. This paper highlights the benefits of using unmanned aerial systems (UASs) for precision spraying applications of pesticides, reducing the environmental risk and waste caused by spray drift. Several unmanned aerial spraying system (UASS) operation parameters and spray system designs are examined to define adequate configurations for specific treatments. A hexarotor DJI Matrice 600 equipped with T-Motor “15 × 5” carbon fiber blades is tested numerically using computational fluid dynamics (CFD) and experimentally in a wind tunnel. These tests assess the aerodynamic interaction between the wake of an advancing multicopter and the fine droplets generated by atomizers traditionally used in agricultural applications. The aim of this research is twofold. First, we analyze the effects of parameters such as flight speed (0, 2, and 3 m·s−1), nozzle type (hollowcone and fan), and injection pressure (2–3 bar) on spray distribution. In the second phase, we use data from the experimental campaign to validate numerical tools for the simulation of rotor–droplet interactions necessary to predict spray’s ground footprint and to plan a precise guidance algorithm to achieve on-target deposition and reduce the well-known droplet drift problem.

/pdf/numerical-analysis-and-wind-tunnel-validation-of-droplet-20dl0yaf.pdf

Numerical Analysis and Wind Tunnel Validation of Droplet Distribution in the Wake of an Unmanned Aerial Spraying System in Forward Flight

The evolution of technology has made increasingly advantageous the introduction of Unmanned Aerial Systems (UASs) in various applications, especially by exploiting their ability for autonomous flight. This paper presents an innovative approach to simulating UAS maneuvers that integrates a Computational Fluid Dynamics (CFD) model and a closed-loop control algorithm for both position and attitude dynamics. We chose the Proportional-Integrative-Derivative (PID) controller for this preliminary research activity because of its simple implementation and widespread employment in commercial autopilot systems. The numerical simulation of the UAS aerodynamics allows for performing an accurate analysis in critical situations. These include, for example, ground effect or wind gusts scenarios, which require an enhanced propulsive model to capture the interaction between vehicle dynamics, aerodynamics, and environmental conditions. The coupled CFD/PID framework can be a virtual testing environment for UAS platforms. Here we report on its validation. The paper compares such an innovative in-the-loop CFD approach and a classical simplified propulsive model that adopts constant thrust and torque coefficients. 

Assessment of Quadrotor PID Control Algorithms using six-Degrees of Freedom CFD simulations

The evolution of technology has made increasingly advantageous the introduction of Unmanned Aerial Systems (UASs) in various applications, especially by exploiting their ability for autonomous flight. This paper presents an innovative approach to simulating UAS maneuvers that integrates a Computational Fluid Dynamics (CFD) model and a closed-loop control algorithm for both position and attitude dynamics. We chose the Proportional-Integrative-Derivative (PID) controller for this preliminary research activity because of its simple implementation and widespread employment in commercial autopilot systems. The numerical simulation of the UAS aerodynamics allows for performing an accurate analysis in critical situations. These include, for example, ground effect or wind gusts scenarios, which require an enhanced propulsive model to capture the interaction between vehicle dynamics, aerodynamics, and environmental conditions. The coupled CFD/PID framework can be a virtual testing environment for UAS platforms. Here we report on its validation. The paper compares such an innovative in-the-loop CFD approach and a classical simplified propulsive model that adopts constant thrust and torque coefficients.

Manuel Carreno Ruiz

Papers

Experimental and numerical analysis of multicopter rotor aerodynamics