Achieving high performance in fixed-wing, unmanned aerial systems necessitates efficient wing assemblies which often entail significant design and production costs. Balancing measures associated with performance, production, reliability, and maintainability adds further complexity to wing design. I present here my current work on the use of Cellular Compressive Wing (CCW) architecture as a viable solution for achieving low structural mass and high flight efficiency while simultaneously enhancing production, maintainability, and reducing costs. To confirm the approach, a wing planform utilizing CCW has been developed based on specific aircraft performance requirements. Computational Fluid Dynamics and Finite Element Analysis have been leveraged to generate estimates of dynamic planform load distributions and CCW interface load characteristics. These simulation methods have in turn been used to guide the design of wing cell interfaces optimized for additive manufacturing techniques employing photopolymers and composite thermopolymers. Application-specific bench-test and in-flight hardware are currently being constructed and tested for direct experimental validation of dynamic planform and CCW interface loads.

While discussing as a group what types of experimentation we could potentially do, we had a variety of different ideas. We thought that with the DC plasma source available to us, it would be interesting to compare how the cleanliness of the vacuum chamber impacted when breakdown would occur. For our research, we are using a DC Plasma Discharge device, which creates a plasma between two electrodes inside of a vacuum chamber. A high DC (direct current) voltage is applied across the two electrodes and a current flows between them. Plasma, the 4th state of matter, is a gas where electrons have been stripped from atoms or molecules in a gas. What results is an electrically charged gas consisting of negative electrons and positive ions. The point at which a gas becomes a plasma is called breakdown. Breakdown depends on the pressure in the vacuum vessel, the distance between the electrodes, the type of gas and the voltage applied. A Paschen curve relates the breakdown voltage to the product of the distance between the electrodes and the pressure in the vacuum vessel. Our goal was to see how a dirty vacuum chamber would impact the Paschen curve. We expected that breakdown would happen at lower voltages with the clean vacuum chamber. We obtained data for creating the curve by running the plasma tube and measuring the pressure as the voltage increased while the vacuum chamber was contaminated with oil. We recorded pressure and voltage values for when breakdown occured and repeated this process with different distances. We then gathered the same data after the vacuum was cleaned. The implication of our research is that it will add to information on how the cleanliness of a vacuum chamber determines when breakdown happens in a plasma tube. In the future, more trials could be run and different gases could be tested. 

The purpose of this experiment was to visualize and record the different rates of expansion for multiple gases as they are launched into the higher parts of Earth’s atmosphere with a High-Altitude Balloon (HAB). The ideal gas law models the behavior of a gas that of which its molecules occupy no volume and have no intermolecular forces (IMF). It is a simple equation; however, it cannot model gases accurately. On the other hand, Van der Waals equation for non-ideal gases better resembles the behavior of a real gas as it includes what the ideal gas law lacks. To test this, we filled three syringes with three different gases to the same volume. We chose to test argon, helium, and nitrogen. We secured the syringes to a container, which served as the payload for the HAB. We also placed an altimeter, thermometer, and a barometric pressure sensor inside the container. Then, we connected the sensors to an Arduino to record each piece of data synced to a stopwatch that is displayed in the container on a screen. Finally, we secured a camera to the container facing the stopwatch and syringes to record the gasses’ volume. Because helium has the weakest IMFs out of the three gases, we believed helium would expand at a higher rate as atmospheric pressure decreases compared to the other gases. The results from our experiment serve as a good example of how far the behavior of real gases deviate from ideal gases modeled by the ideal gas law. Depending on how close our measured values reach the calculated values from the ideal gas law, we can predict which situations the ideal gas law can model the behavior of a particular gas relatively accurately.

Accurately modeling atmospheric re-entry has become incredibly important with the advent of reusable spacecraft. Computational Fluid Dynamic (CFD) employs solvers, a combination of mathematical models, to attempt to replicate real-world physical characteristics, such as when a spacecraft is re-entering the atmosphere. This research attempts to validate the OpenFOAM hy2Foam solver–which was created to model the environment of atmospheric re-entry–by comparing CFD results to real-world wind tunnel data of the hypervelocity ballistic model 1 (HB-1) at mach 5.1. We show with 99% confidence that the CFD simulations do not produce numerically accurate results when compared to historical wind tunnel data at seven varying angles of attack: -1, 0, 2, 4, 6, 8, 10, and 12 degrees. For all angles of attack, the forebody axial-force coefficient disagrees with historical wind tunnel testing, being 2.38 times less on average. Additionally, for all but the -1 and 0 degree angle of attack, the pitching-moment coefficient disagrees with the historical data, being 52.6 times less on average. Additional research conducted on the HB-2 model has found similar disagreement of aerodynamic results demonstrating a need for additional research to ensure the solver produces numerically accurate results. Accurate solvers are vital to ensure that CFD simulations accurately model real-world conditions, such as during spacecraft re-entry when safety of astronauts could be at stake if a spacecraft is designed based on invalid data.