Aerodynamics of the Drone Prototype
In the exciting journey of designing our drone prototype, particularly when sculpting its outer shell, we encountered crucial aerodynamic considerations. Two primary questions emerged: firstly, how might aerodynamic factors influence the drone's flight behavior, and secondly, whether the companion computer, nestled in the drone's lower body, would receive adequate airflow for cooling during forward flight. To address these queries, we partnered with AirShaper to perform a comprehensive Computational Fluid Dynamics (CFD) analysis. This blog post delves into the details of our CFD study and unveils the intriguing findings.
Simulation Setup
We utilized AirShaper for our simulation, a platform where setting up a CFD analysis is remarkably quick and user-friendly. The process was straightforward: we uploaded an STL file of the drone, specified parameters such as wind speed and the drone's pose, and we were set to start. Notably, AirShaper supports simulations with rotating objects, an essential feature for analyzing the dynamics of the drone's propellers. The figure below illustrates how we configured our simulation within the AirShaper environment.
Drone Drag Optimization
In the context of drone aerodynamics, drag is a crucial factor that becomes increasingly significant at higher speeds. Analyzing drag involves identifying which parts of the drone create the most resistance to air flow. A typical method for visualizing these areas is through simulations that highlight low pressure zones, often the primary contributors to drag.
In the video below, low pressure zones are highlighted in red. These zones indicate where the air pressure is lower than the surrounding environment, usually due to the shape and movement of the drone. Air naturally moves from areas of high pressure to low pressure, so these red zones are where the air is effectively 'pulling' on the drone, increasing drag.
Air Intake for Internal Companion Computer Cooling
Ensuring consistent airflow around the heatsink of the companion computer is vital for the effective cooling of the drone's internal components. The heart of our drone is an Nvidia Jetson Nano, integrated into the lower body of the drone. To facilitate air circulation, the drone's shell features an air intake at the front, strategically designed to channel airflow through the heatsink of the Jetson board. The figure below provides a clear view of how the companion computer is positioned within the drone's structure.
In scenarios of aggressive forward flight, particularly at angles up to 45°, the air intake of the drone's shell tilts downwards. This orientation prompts critical questions about airflow dynamics: Does sufficient air enter the drone's shell, or does airflow separation occur at the nose, compromising the cooling of the companion computer? To investigate this, we utilized CFD analysis to visualize the velocity of air inside the shell.
The figure below reveals a key insight: the air velocity within the shell is nearly identical to that of the surroundings. Based on this observation, we infer that the airflow should be adequate to efficiently cool the companion computer.
All data for this analysis is availably at AirShaper