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 …

Construction Of Naca 66-415 Nlf Composite Wing For Acoustic Turbulence Testing, Scott Sawyer, Sean Stewart

Aerospace Engineering

A design is developed for a Natural Laminar Flow (NLF) wing, to be used at California Polytechnic State University for acoustic turbulence testing. Composite materials are used to produce high-quality surface finishes necessary for laminar flow. A design for the test apparatus is presented and justified. A manufacturing procedure is proposed for the carbon fiber skin, using Vacuum Resin Infusion (VRI). This procedure is tested on a scaled part with satisfactory results; lessons learned are discovered and integrated into the final manufacturing process. The test section has been fit to the Cal Poly wind tunnel, but full implementation has not …

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 …

Port Flow Test System, Daniel Chairez, Chelsea E. Crawford, Daniel S. Welch

Mechanical Engineering

Solar Turbines Gas Compressor Engineering Division of San Diego, California called upon the Mechanical Engineering students of California Polytechnic University, San Luis Obispo to provide recommendations for optimization of compressor end cap port design. Various sizes of compressors have end caps with numerous ports that exchange fluids between the inside and outside of the working fluid pressure vessel. Because so many ports must exist on the end caps, unusual flow paths are created to supply the appropriate location within the compressor. These flow paths commonly consist of a drilled inlet hole which intersects with a sudden expansion. The sudden expansion …

Rayleigh Test Apparatus Design Report, Josef Duller, Owen Raybould, James Nicovich

Mechanical Engineering

The Rayleigh Test Apparatus is a device that will be used to test the thermodynamic properties of Nitrous Oxide to assess the feasibility of using this fluid as a coolant for a hybrid rocket aero spike. The aero spike is intended to redirect the propulsion flow as it leaves the engine to create a more efficient flow pattern at low and high altitudes. However, there are issues of overheating which leads to melting of the aero spike. For this reason, the use of nitrous oxide (N2O) as a coolant is being explored. N20 is being considered because it is already …

Human Powered Helicopter: Observing The Impacts Of Ground Effect And Intermeshed Rotors, Shane Stowe

Physics

No abstract provided.

Designing The Human-Powered Helicopter: A New Perspective, Gregory Hamilton Gradwell

Master's Theses

The concept of human-powered vertical flight was studied in great depth. Through the manipulation of preexisting theory and analytical methods, a collection of design tools was created to expediently conceptualize and then analyze virtually any rotor. The tools were then arranged as part of a complete helicopter rotor design process. The lessons learned as a result of studying this process—and the tools of which it consists—are presented in the following discussion. It is the belief of the author that by utilizing these tools, as well as the suggestions that accompany them, future engineers may someday build a human-powered helicopter capable …

A Computational Study Of Engine Deflection Using A Circulation Control Wing, Bryan Holly Blessing

Master's Theses

In the past, research into Short Takeoff and Landing aircraft has led to the investigation of the coupling of a Circulation Control Wing and Upper Surface Blowing engine. The Circulation Control Wing entrains the flow of the engine to be deflected downward such that a component of the thrust is now in the vertical direction. The unfortunate consequence of the Upper Surface Blowing engine is the poor cruise performance due to scrub drag. Cal Poly's research into a Cruise Efficient Short Takeoff and Landing Aircraft offers a solution by pylon mounting over the wing engines. Analysis shows that the engine …

High-Frame-Rate Oil Film Interferometry, Jonathan Charles White

Master's Theses

High-Frame-Rate Oil Film Interferometry

Jonathan Charles White

This thesis presents the design and implementation of a high-frame-rate oil film interferometry technique (HOFI) used to directly measure skin friction in time dependent flows. Experiments were performed to determine the ability of a high-speed camera to capture oil film interferometry images. HOFI was found to be able to capture these interferometry images at frequencies up to 10⁵ Hz. Steady laminar and turbulent flows were tested. Transient flows tested consisted of a wind tunnel ramping up in velocity and a laminar boundary layer which was intermittently tripped to turbulence by puffing air …

Conical Probe Calibration And Wind Tunnel Data Analysis Of The Channeled Centerbody Inlet Experiment, Samson Siu Truong

Aerospace Engineering

For a multi-hole test probe undergoing wind tunnel tests, the resulting data needs to be analyzed for any significant trends. These trends include relating the pressure distributions, the geometric orientation, and the local velocity vector to one another. However, experimental runs always involve some sort of error. As a result, a calibration procedure is required to compensate for this error. For this case, it is the misalignment bias angles resulting from the distortion associated with the angularity of the test probe or the local velocity vector. Through a series of calibration steps presented here, the angular biases are determined and …

Scale Modeling Of Cessna 172, Chee-Woon Kim

Aerospace Engineering

This report describes how the scale-model aircraft can be built when the Reynolds number is out of range for using dynamic similitude method. Due to lack of time and budget for designing an actual model for testing, Cessna 172 was used to calculate the size of the temporary scale-model aircraft. The method that was used for this project was matching aerodynamic coefficients such as drag coefficient or lift coefficient of the prototype and the model. Based on this method, the takeoff distance, landing distance and the rate of climb of the model came out to be 218 ft, 91 ft …

Two Element Linear Strength Vortex Panel Method, Clifton A. Cox

Aerospace Engineering

A linear strength vortex panel method was developed to predict the C_p and C_l for a lifting two element airfoil. The linear strength vortex panel method was first validated against thin airfoil theory and experimental data for a single NACA 2412 airfoil. At 2 degrees angle of attack, the linear strength vortex panel method predicted a C_l of about 0.49. Experimental data and thin airfoil theory gave C_l estimations of 0.45 and 0.22 respectively. The Matlab code was then modified to accept a two element airfoil. The two key modifications were the separation of the two …

An Investigative Study Of Gurney Flaps On A Naca 0036 Airfoil, Gregory F. Altmann

Master's Theses

This project examined the effect of Gurney flaps on a 2D, 2-ft chord NACA 0036 airfoil in the Cal Poly 3’x4’ low speed wind tunnel at 25 m/s. It also covered the numerical simulation of the experiment in computational fluid dynamics (CFD). During the study, problems with the wind tunnel data were seen. After a careful diagnosis, the problem was traced to dirty flow conditioners which were subsequently replaced.

Five Gurney flaps at 1, 2, 3, 4, and 5% of the chord were tested. The Gurney flaps had the effect of eliminating the lift reversal effect and lowering the profile …

Analysis Of Surface Augmentation Of Airfoil Sections Via Flow Visualization Techniques, John Louis Vento

Aerospace Engineering

This report details an experiment done to verify the effectiveness of two passive flow control systems on two-dimensional airfoil sections. The flow control was tested on two types of airfoils: a symmetric NACA 0011, intended to represent an airplane in cruise, and a NACA16611, intended to represent an aircraft with flaps extended. Two types of passive systems were employed, a dimple surface augmentation, similar to a golf ball, and a grit system located at 20% chord. Airfoils without either augmentation were tested as a control case. Using a water tunnel and dye to perform flow visualization, the effects of each …