Aerodynamics and Fluid Mechanics Commons^™

Investigation Of Conjugate Heat Transfer In Fluid-Structure Interaction Modeling Using Openfoam, Andrew Brown

Aerospace Engineering

No abstract provided.

Particle Image Velocimetry Of Transverse Jets In Crossflow, Jesse K. Tsai, Kayla Kuzmich, David Forliti, Kriss Vanderhyde, Nils Sedano

STAR Program Research Presentations

The jet in crossflow (JICF) has been an ongoing study for the past several decades with applications in the field of fluid mechanics. This particular flow field produces vortical structures tied to the entrainment and mixing of two separate fluids. Research of the JICF seeks to determine a model and trajectory scaling law for future designs. This will help future designers to optimize the mixing and homogeneity of the two fluids to decrease emissions from pollutants, make ignition easier, and improve combustion efficiency of rockets.

Our experiment will employ Particle Image Velocimetry (PIV) to determine the fluid motion of the …

Effect Of Adaptive Tabs On Drag Of A Square-Base Bluff Body, Brian W. Barker

Master's Theses

This thesis involves the experimental wind tunnel testing of a 0.127m by 0.127m square-base bluff body to test the effectiveness of trailing edge tabulations to reduce drag in the Cal Poly 0.912m by 1.219 m low-speed wind tunnel. To accomplish this, the boundary layer was first measured on the trailing edge of the model for the three speeds at 10, 20, and 30 m/s, with Re = 8.3e4, 1.6e5 and 2.5e5 respectively, without the tabs. Three different tests were performed to determine the effectiveness of the tabs. These tests included base pressure measurements, total drag force measurements and hotwire velocity …

Experimental Investigation Of Active Wingtip Vortex Control Using Synthetic Jet Actuators, Peter J. Sudak

Master's Theses

An experiment was performed in the Cal Poly Mechanical Engineering 2x2 ft wind tunnel to quantify the effect of spanwise synthetic jet actuation (SJA) on the drag of a NACA 0015 semispan wing. The wing, which was designed and manufactured for this experiment, has an aspect ratio of 4.20, a span of 0.427 m (16.813”), and is built around an internal array of piezoelectric actuators, which work in series to create a synthetic jet that emanates from the wingtip in the spanwise direction. Direct lift and drag measurements were taken at a Reynolds Number of 100,000 and 200,000 using a …

On The Growth Rate Of Turbulent Mixing Layers: A New Parametric Model, Jeffrey L. Freeman

Master's Theses

A new parametric model for the growth rate of turbulent mixing layers is proposed. A database of experimental and numerical mixing layer studies was extracted from the literature to support this effort. The domain of the model was limited to planar, spatial, nonreacting, free shear layers that were not affected by artificial mixing enhancement techniques. The model is split into two parts which were each tuned to optimally fit the database; equations for an incompressible growth rate were derived from the error function velocity profile, and a function for a compressibility factor was generalized from existing theory on the convective …

Flight And Stability Of A Laser Inertial Fusion Energy Target In The Drift Region Between Injection And The Reaction Chamber With Computational Fluid Dynamics, Tiffany Leilani Mitori

Master's Theses

A Laser Inertial Fusion Energy (LIFE) target’s flight through a low Reynolds number and high Mach number regime was analyzed with computational fluid dynamics software. This regime consisted of xenon gas at 1,050 K and approximately 6,670 Pa. Simulations with similar flow conditions were performed over a sphere and compared with experimental data and published correlations for validation purposes. Transient considerations of the developing flow around the target were explored. Simulations of the target at different velocities were used to determine correlations for the drag coefficient and Nusselt number as functions of the Reynolds number. Simulations with different target angles …

Evolution Of Perturbations In Flow Field Mechanics, Samantha R. Bell, David Forliti, Nils Sedano, Kriss Vanderhyde

STAR Program Research Presentations

This project explores the stability analysis of a given flow field. Specifically, where the peak disturbance occurs in a flow as this is the disturbance that is most likely to occur. In rocket combustion, it is important to understand where the maximum disturbance occurs so that the mixing of fuel can be stabilized. The instabilities are the results of frequencies in the area surrounding the flow field. The linear stability governing equations are employed to better understand the disturbance. The governing equations for continuity and momentum in the x and y directions are used to form an equation for the …

Adaptive Control Techniques For Transition-To-Hover Flight Of Fixed-Wing Uavs, Brian Decimo Marchini

Master's Theses

Fixed-wing unmanned aerial vehicles (UAVs) with the ability to hover combine the speed and endurance of traditional fixed-wing fight with the stable hovering and vertical takeoff and landing (VTOL) capabilities of helicopters and quadrotors. This combination of abilities can provide strategic advantages for UAV operators, especially when operating in urban environments where the airspace may be crowded with obstacles. Traditionally, fixed-wing UAVs with hovering capabilities had to be custom designed for specific payloads and missions, often requiring custom autopilots and unconventional airframe configurations. With recent government spending cuts, UAV operators like the military and law enforcement agencies have been urging …

Computational And Experimental Comparison Of A Powered Lift, Upper Surface Blowing Configuration, Jay M. Marcos

Master's Theses

In the past, 2D CFD analysis of Circulation Control technology have shown poor comparison with experimental results. In Circulation Control experiments, typical results show a relationship between lift coefficient, CL, vs blowing momentum coefficient, Cμ. CFD analysis tend to over-predict values of CL due to gridding issues and/or turbulence model selection. This thesis attempted to address both issues by performing Richardson’s Extrpolation method to determine an acceptable mesh size and by using FLUENT’s 2-equation turbulence models. The experimental results and CAD geometry were obtained from Georgia Tech Research Institute for comparison with the CFD analysis.

The study showed that 3D …

Qualitative Methods Used To Develop And Characterize The Circulation Control System On Cal Poly's Amelia, Eric N. Paciano

Master's Theses

The circulation control system onboard Cal Poly's Advanced Model for Extreme Lift and Improved Aeroacoustics was a critical component of a highly complex wind tunnel model produced in order to fulfill the requirements of a NASA Research Announcement awarded to David Marshall of the Aerospace Engineering Department. The model was based on a next generation, 150 passenger, regional, cruise efficient, short take-off and landing concept aircraft that achieved high lift through circulation control wings and over-the-wing mounted engines. The wind tunnel model was 10-ft in span, used turbine propulsion simulators, and had a functioning circulation control system driven from tunnel …

Microphone-Based Pressure Diagnostics For Boundary Layer Transition, Spencer Everett Lillywhite

Master's Theses

An experimental investigation of the use low-cost microphones for unsteady total pressure measurement to detect transition from laminar to turbulent boundary layer flow has been conducted. Two small electret condenser microphones, the Knowles FG-23629 and the FG-23742, were used to measure the pressure fluctuations and considered for possible integration with an autonomous boundary layer measurement system. Procedures to determine the microphones’ maximum sound pressure levels and frequency response using an acoustic source provided by a speaker and a reference microphone. These studies showed that both microphones possess a very flat frequency response and that the max SPL of the FG-23629 …

Ramjet Combustion Chamber, Paul Cameron Stone

Aerospace Engineering

A ramjet combustion chamber is designed and some initial assembly fabrication and test completed as a component of a ramjet graduate project for California Polytechnic State University, San Luis Obispo Supersonic Wind Tunnel. The combustor design is driven by a theoretical model created by a Cal Poly graduate student, Harrison Sykes. Temperature, pressure, and fuel flow will be measured.

Design And Fabrication Of A Ramjet Engine, Clinton C. Humphrey

Aerospace Engineering

In this report, the design and fabrication of the inlet to a ramjet engine is described. The inlet utilizes a single ramp and single sided three shock internal compression to slow the airflow from supersonic to subsonic speeds while providing maximum stagnation pressure to the combustor. The optimum angle for the inlet ramp is calculated to be 10° and it decelerates the airflow from Mach 3.3019 to Mach 0.5438. The stagnation pressure increases from 150 psi to 4.67 ksi. The material of the inlet is composed primarily of low carbon mild steel to accommodate the high pressure of the inlet.

Incorporating Aluminum Honeycomb To Increase Efficiency Of U-Tube Removable Heat Exchanger, Daniel Soto, Daniel Corona

Aerospace Engineering

This report contains the results of attempting to improve on the results of Scott R. Sawyer and Alan M. L’Esperance research paper “Investigation of Paraffin Wax as an Energy Storage Medium Within a Shell-and-Tube Heat Exchanger.” The overall goal of the paper mentioned was to investigate the usefulness of wax as an energy storage medium. Scott R. Sawyer and Alan M. L’Esperance determined that “the amount of energy that can be released by the paraffin wax back to the airflow reaches a plateau, despite an increase in heating times.” They suggested that by surrounding the airflow tubes of a heat …

Design And Performance Of Circulation Control Geometries, Rory Martin Golden

Master's Theses

With the pursuit of more advanced and environmentally-friendly technologies of today’s society, the airline industry has been pushed further to investigate solutions that will reduce airport noise and congestion, cut down on emissions, and improve the overall performance of aircraft. These items directly influence airport size (runway length), flight patterns in the community surrounding the airport, cruise speed, and many other aircraft design considerations which are setting the requirements for next generation aircraft. Leading the research in this movement is NASA, which has set specific goals for the next generation regional airliners and has categorized the designs that meet the …

Distributed Forcing On A 3d Bluff Body With A Blunt Base, An Experimental Active Drag Control Approach, Ethan Bruce Erlhoff

Master's Theses

This paper seeks to explore the effects of an active drag control method known as distributed forcing on a 3D bluff body with a blunt base. The 9.5 x 15.25 x 3 inch aluminum model constructed for this experiment has an elliptically shaped nose and rectangular aft section. The model is fitted with four, 12 Volt fans, forcing the freestream air into and out of 1 mm thick slots on the upper and lower trailing edges. The forcing is steady in time, held at a constant forcing velocity though all Reynolds numbers, but varies roughly sinusoidally in the spanwise direction …

Confined Mixing Of Multiple Transverse Jets, Allen J. Bishop

Master's Theses

The mixing performance of multiple transverse jets has been evaluated experimentally. Measurement techniques included laser Doppler velocimetry and planar laser induced fluorescence. Basic findings are consistent with results presented in literature for single jet mixing behavior. Mixing performance has been compared to literature for the single jet case and the Holdeman parameter has been re-evaluated for effectiveness at low jet numbers. A single jet in a confined crossflow was found to have a local minimum at B(d⁄D) = 0.721. Results for two jets indicate monotonically decreasing unmixedness for the range of conditions tested, with no local optimum apparent. Data for …

Analysis Of A Goldschmied Propulsor Using Computational Fluid Dynamics Referencing California Polytechnic's Goldschmied Propulsor Testing, Cory A. Seubert

Master's Theses

The Goldschmied Propulsor is a concept that was introduced in mid 1950's by Fabio Goldschmied. The concept combines boundary layer suction and boundary layer ingestion technologies to reduce drag and increase propulsor efficiency. The most recent testing, done in 1982, left questions concerning the validity of the results. To answer these questions a 38.5in Goldschmied Propulsor was constructed and tested in Cal Poly's 3x4ft wind tunnel. The focus of their wind tunnel investigation was to replicate Goldschmied's original testing and increase the knowledge base on the subject. The goal of this research was to create a computational fluid dynamics (CFD) …

Hot-Wire Anemometer For The Boundary Layer Data System, William D. Neumeister

Master's Theses

Hot-wire anemometry has been routinely employed for laboratory measurements of turbulence for decades. This thesis presents a hot-wire anemometer suitable for use with the Boundary Layer Data System (BLDS). BLDS provides a unique platform for in- flight measurements because of its small, self-contained, robust design and flexible architecture. Addition of a hot-wire anemometer would provide BLDS with a sensor that could directly measure flow velocity fluctuations caused by turbulence. Hot-wires are commonly operated in constant-temperature mode for high frequency response, but require a carefully tuned bridge. The constant-voltage anemometer (CVA) uses a simple op-amp circuit to improve frequency response over …

Test And Verification Of Vortex Shedding For A 3d Bluff Body, Paul D. Innes, Charles E. Carlson

Aerospace Engineering

Testing of a 3D bluff body with and without end plate tabs was performed in the California Polytechnic State University 3x4 ft low speed wind tunnel. The C_P values were obtained for the test case with no end plate tabs for speeds of 10, 15, 20, and 30 m/s. It was observed that stronger vortex shedding ocured at the higher speed test cases. The model was shimmed to be at approximately 5° angle of attack in order to obtain symmetrical negative C_P spikes for the top and bottom of the model without tabs. Trends were observed and compared …

Thermal Vacuum Integration For Cal Poly's Space Environments Laboratory, Chelsea Barackman, Steven Jackowski

Aerospace Engineering

The purpose of the senior project is to construct a thermal vacuum by utilizing a preexisting vacuum chamber in the Space Environments Lab, and a donated Advanced Thermal Sciences (ATS) chiller. While a thermal vacuum is already available on campus, building one for the Space Environments Lab would grant undergraduates access to the equipment, allowing a much better understanding of testing methods and procedures in use by the aerospace industry. This paper explains the design and analysis of the thermal vacuum (T-VAC) project as well as the operation and procedures required for the ATS chiller and fill/drain tank. The thermal …

Aerodynamic Test Platform For Human Powered Vehicle (Hpv), Spencer Wangerin, Spencer Lillywhite, Colburn Davis

Mechanical Engineering

The Aerodynamic Test Platform (ATP) for the Cal Poly HPV Club is a system that was designed by Cal Poly mechanical engineering students to measure aerodynamic characteristics of a human-powered vehicle (HPV). The HPV team desired a system that could quantify the lift, drag, and other aerodynamic qualities of a full scale HPV at various orientations in oncoming airflow. Established methods for determining aerodynamic characteristics include computational fluid dynamics (CFD) and wind tunnel testing of scaled models. The ATP was devised to simulate the test results given by a full-scale wind tunnel without requiring a wind tunnel large enough to …

Experimental Investigation Of A 2-D Air Augmented Rocket: High Pressure Ratio And Transient Flow-Fields, Josef S. Sanchez

Master's Theses

A 2-D Air Augmented Rocket, the Cal Poly Air Augmented Rocket (CPAAR) Test Apparatus operating as a mixer-ejector was tested to investigate high stagnation pressure ratio and transient flow fields of an ejector. The primary rocket ejector was supplied with high pressure nitrogen at a maximum chamber pressure of 1758 psia and a maximum mass flow rate of 1.4 lb/s. The secondary flow air was entrained from a fixed volume plenum chamber producing pressures as low as 3.3 psia. The maximum total pressure ratio achieved was 221. The original CPAAR apparatus was rebuilt re-instrumented and capability expanded. A fixed volume …

Effect Of End-Plate Tabs On Drag Reduction Of A 3d Bluff Body With A Blunt Base, Jarred Michael Pinn

Master's Theses

This thesis involves the experimental testing of a bluff body with a blunt base to evaluate the effectiveness of end-plate tabs in reducing drag. The bluff body is fitted with interchangeable end plates; one plate is flush with the rest of the exterior and the other plate has small tabs protruding perpendicularly into the flow. The body is tested in the Cal Poly 3ft x 4ft low speed wind tunnel. Testing is conducted in three phases.

The first phase was the hot-wire measurement of streamwise velocity of the near wake behind the bluff body. An IFA300 thermal anemometry system with …

Experimental Investigation Of Suction Slot Geometry On A Goldschmied Propulsor, Nicole M. Thomason

Master's Theses

The Goldschmied Propulsor concept combines boundary layer suction and boundary layer ingestion to improve propulsive efficiency and reduce drag on an axisymmetric body. This investigation of a Goldschmied Propulsor aimed to determine influential characteristics of the suction slot geometry to aid in better slot geometry design and to decrease the suction flow requirements for maintaining attached flow over the entire model surface. The Propulsor model was 38.5 inches in length with a max diameter of 13.5 inches. Three suction slot geometries were investigated with the addition of aluminum cusps to the slot entrance. The cusps varied in the distance they …

Implementation And Validation Of The Ζ-F And Asbm Turbulence Models, Dustin Van Blaricom Quint

Master's Theses

The use of Computational Fluid Dynamics (CFD) tools throughout the engineering industry has become standard. Simulations are used during nearly all steps throughout the life cycle of products including design, production, and testing. Due to their wide range of use, industrial CFD codes are becoming more flexible and easier to use. These commercial codes require robustness, reliability, and efficiency. Consequently, linear eddy viscosity models (LEVM) are used to model turbulence for an increasing number of flow types. LEVM such as k-ε and k-ω provide modeling with little loss of computational efficiency and have proven to be robust. The LEVM that …

Flow Characteristics Of The Renovated Cal Poly 3 X 4 Ft Subsonic Wind Tunnel, Mathew L. Thomas, Dorian V. Pandey, Jason N. Nguyen

Aerospace Engineering

This paper investigates the flow characteristics of the renovated Cal Poly 3 x 4 ft subsonic wind tunnel. The IFA 300 constant-temperature anemometer along with a cross-plane X-wire dual-sensor probe was used to measure the mean velocity and turbulence intensity of the tunnel flow and part of the turbulent boundary layer at one section of the tunnel. Because of the malfunction of one channel of the IFA 300, only one wire of the dual sensor probe was calibrated for the measurements. The probe was then placed in a streamlined probe holder mounting on the traverse inside the wind tunnel. The …

Simulation Of Wing Tip Vortices, Ryan Termath, Jason Lechniak, Keerti Bhamidipati

STAR Program Research Presentations

Modeling and Simulation (M&S) computational fluid dynamics (CFD) techniques were used to better understand wing tip vortices about a wing section. The CFD results were compared to experimental wind tunnel data derived from the University of Iowa (Ref. 2). The experiment used Stereoscopic Particle Image Velocimetry (SPIV) to measure the flow field. The SPIV data from the experiment illustrates the vortex core development and behavior downstream of the trailing edge of the wing section. Three CFD simulations using various mesh sizes and time steps were completed and compared to the experimental results. Two dimensional plots of modeled local flow field …

Unsteady Total Pressure Measurement For Laminar-To-Turbulent Transition Detection, Akane Sharon Karasawa

Master's Theses

This thesis presents the use of an unsteady total pressure measurement to detect laminar-to-turbulent transition. A miniature dynamic pressure transducer, Kulite model XCS-062-5D, was utilized to measure the total pressure fluctuations, and was integrated with an autonomous boundary layer measurement device that can withstand flight test conditions. Various sensor-probe configurations of the Kulite pressure transducer were first examined in a wind tunnel with a 0.610 m (2.0 ft) square test section with a maximum operational velocity of 49.2 m/s (110 mph), corresponding dynamic pressure of 1.44 kPa (30 psf). The Kulite sensor was placed on an elliptical nose flat plate …

Design, Manufacturing And Testing Of An Environmentally-Green Bipropellant Thruster, Alex Bendoyro, Gabriel Sanchez, Erin Stearns, Phillip Takahashi

Aerospace Engineering

This project reviews the design, manufacturing and experimentation process of a green bi-propellant thruster designed to output 5 lbf. The goals were to successfully design, manufacture and test a thruster, while discovering the complications that arise through out the complete design process of a green thruster. The thruster was successfully designed using ideal rocket equations and the design was successfully confirmed using CFD and FEA. Manufacturing of the thruster was fully planned and revealed mild flaws in thruster design. For example some features were not manufacturable to the exact measurements desired. Testing of the engine gave results inconsistent with expected …