Undergraduate Fluid Mechanics Research Articles

DIY-PIV system for Poiseuille flow investigation in undergraduate fluid mechanics course

Fluid flow visualization techniques are becoming more widespread every year due to the availability of lasers, high-speed cameras, and the development of a large amount of image processing software. Nowadays, one of the most popular methods of flow optical visualization is particle image velocimetry (PIV). PIV is an innovative way to measure and analyze fluid characteristics, giving students a more in-depth understanding of how fluids move. This paper is focused on using low-cost components and free software to implement PIV for Poiseuille flow investigation in an undergraduate fluid mechanics course. The introduction discusses how PIV is being used as a complementary method in educational institutions, highlights the high cost of equipment to implement PIV, and gives examples of low-cost do-it-yourself (DIY)-PIV systems. The following sections present the theoretical background, descriptions of the DIY-PIV experimental setup, and plan of the investigation for the Poiseuille flow analysis. A brief overview of free image processing software for the PIV implementation is also provided. The last section presents the results of the Poiseuille flow study and analyzes the measurement quality using the created DIY-PIV system. The present experimental investigation covers topics and reinforces skills related to concepts: laminar flow, Poiseuille flow (velocity distribution, maximum and average velocity), Reynolds number, and measurement error.

Combining hands‐on and virtual experiments for enhancing fluid mechanics teaching: A design‐based research study

AbstractFluid Mechanics courses comprise both theoretical and laboratory modules. In developing nations, computer‐assisted techniques are not commonly applied in Fluid Mechanics instruction. Forced by the COVID‐19 pandemic, South American universities are, however, using them for online teaching. This contribution presents an 8‐semester (2016–2019) educational intervention over an undergraduate Fluid Mechanics course. It mainly blends physical (hands‐on) and virtual experiments (computer fluid dynamics‐based simulations) for the laboratory module, which are complemented by flipped classroom‐based prompts for the theoretical module. The intervention follows design‐based research as a research method and is guided via conjecture mapping and fidelity of implementation standards. Our results suggest that the intervention improves fluid mechanics laboratory instruction, although improvements depend upon the participation of other educational actors such as teaching assistants and laboratory technicians to some extent. Laboratory report grades (the assessment instrument) follow the Gompertz probability distribution. Following UNESCO standards, a portion of the intervention output is shared as open educational resources. This contribution encourages upscaling the educational intervention through the formation of cooperative clusters to build common‐pool Fluid Mechanics resources. Learning scientists have underlined the need to better understand laboratory instruction processes. They have been addressed in very few instances in developing countries. We believe that this study has the potential to provide valuable insights on the matter.

Computational Solvers for Iterative Hydraulic loss Calculations in Pipe Systems

Abstract —The study of fluid mechanics spans several engineering disciplines including Mechanical, Civil, Aerospace, Chemical, Environmental, Petroleum, and Biomedical Engineering. In all these disciplines, hydraulic loss calculations in pipes are extremely important. However, the iterative nature of the solution to these engineering problems makes it intricate and cumbersome to solve. Further, it gets very difficult to visualize the solutions to such iterative problems for a wide variety of cases. The current paper aims to bridge this gap by the creation of two open-source Excel-VBA based computational solvers. The first tool corresponds to the determination of the Darcy-Weisbach friction factor through the Colebrook Equation and its visualization on a Moody's chart, which can be effectively employed by engineering instructors as an active learning tool. Second, a complete tool covering all four kinds of pipe flow situations (including the iterative problems) has been developed. The developed computational tools were employed in an undergraduate Fluid Mechanics classroom and the detailed student responses were collected on ten aspects related to teaching and learning divided broadly under four categories – 'overall rating', 'student perceptions on self-learning', 'Improvement in teaching delivery', and 'recommendation for other courses'. The data collected from student responses were subjected to statistical analysis. The results of hypothesis testing and the p-value calculations clearly justify the immense usefulness of this tool in the improvement of the overall teaching-learning process of Fluid Mechanics. Finally, the developed computational tools are being hosted free on the web for the benefit of engineering instructors, learners and professionals alike. Keywords:Pipe losses; computational tool; Fluid Mechanics; Hydraulic loss; Moody's chart; Excel VBA.

Opinion: Building Diversity, Equity, and Inclusion into an Engineering Course

Engineering faculty have heard the call to incorporate diversity, equity, and inclusion (DEI) into their classrooms, but many have asked the question: What can I do to advance DEI in my courses? This commentary provides one answer. We summarize our process to engineer DEI into an undergraduate fluid mechanics course following a process that included (1) participation in formal programs, (2) a systematic review of course materials, and (3) a weekly series of conversations that examined DEI in the context of engineering education from academic, social, and personal perspectives. The formal programs deepened our awareness; the systematic review identified improvements in the syllabus, nomenclature, and videos; but most importantly the conversations illuminated how the same technical material can be associated with vastly different cultural perspectives—a key point from the theory of Culturally Relevant Pedagogy. We call for engineering faculty to seek opportunities to learn more of these perspectives, and then to reflect on how to improve their courses accordingly.

Archimedes’ principle with surface tension effects in undergraduate fluid mechanics

The general physics of how objects float is only partly covered in most undergraduate fluid mechanics courses. Although Archimedes’ principle is a standard topic in fluid statics, the role of surface tension in floating is rarely discussed in detail. For example, very few undergraduate textbooks, if any, mention that the total buoyancy force on a floating object includes the weight of the fluid displaced by the meniscus. This leaves engineering students without an understanding of a wide range of phenomena that occur at a low Bond number (the ratio of buoyancy to interfacial tension forces), such as how heavier-than-water objects can float at a gas-liquid interface. This article makes a case for teaching a more unified version of Archimedes’ principle, which combines the effects of surface tension and hydrostatic pressure in calculating the total buoyancy on floating objects. Sample problems at the undergraduate level and two classroom demonstrations are described that reinforce the basic science concepts.

Assessing the effectiveness of a hybrid-flipped model of learning on fluid mechanics instruction: overall course performance, homework, and far- and near-transfer of learning

ABSTRACTTo examine the impact of a hybrid-flipped model utilising active learning techniques, the researchers inverted one section of an undergraduate fluid mechanics course, reduced seat time, and engaged in active learning sessions in the classroom. We compared this model to the traditional section on four performance measures. We employed a propensity score method entailing a two-stage regression analysis that considered eight covariates to address the potential bias of treatment selection. First, we estimated the probability score based on the eight covariates, and second, we used the inverse of the probability score as a regression weight on the performance of learners who did not select into the hybrid course. Results suggest that enrolment in the hybrid-flipped section had a marginally significant negative impact on the total course score and a significant negative impact on homework performance, possibly because of poor video usage by the hybrid-flipped learners. Suggested considerations are also discussed.

Introducing CFD and Wind Tunnel Testing in an Undergraduate Fluid Mechanics Course

Introducing CFD and Wind Tunnel Testing in an Undergraduate Fluid Mechanics Course

Improving Problem-solving Skills of Undergraduates Through Computerized Dynamic Assessment

A computer-based dynamic assessment (DA) system developed for use in an undergraduate fluid mechanics course is presented. Data collected before and after implementation of this DA indicate significant improvement in student performance after implementation. Student performance is quantified by the % of questions correctly answered in the nationally normed Fundamentals of Engineering (FE) Exam relative to the National average. Since implementation of the DA system, this measure for our students has increased from below National level (mean = 0.942; standard deviation, sd = 0.068) to above National level (mean = 1.04; sd = 0.06). For the same population, performance in fluid mechanics has been higher than that in the other subjects where DA was not used (mean = 1.068; sd = 0.028 vs. mean = 0.837; sd = 0.04). Performance of our students in fluid mechanics has exceeded that of their peers in the top tier programs in the U.S. (mean = 1.068; sd = 0.028 vs. mean = 1.031; sd = 0.03).

Experimental Apparatus for Measurements of Two-Phase Slug Flow Pressure Drop in a T-Junction

An experimental test loop system was designed, developed, and constructed to study the two-phase flow field in the undergraduate fluid mechanics laboratory. The purpose of this experimental apparatus is to measure the pressure drop of a two-phase mixture in a tee-junction. This paper describes a fluid mechanics experiment designed for undergraduate students to examine the pressure differences through a T-junction of an air–water mixture in slug two-phase flow regime with equal-sided diameters. This can be carried out at different inlet qualities and extraction rates. Sample results are presented.

Undergraduate teaching of ideal and real fluid flows: the value of real-world experimental projects

This paper describes the pedagogical impact of real-world experimental projects undertaken as part of an advanced undergraduate fluid mechanics subject at an Australian university. The projects have been organized to complement traditional lectures and introduce students to the challenges of professional design, physical modelling, data collection and analysis. An overview of two projects is presented: wind tunnel testing of buildings and wave loading on piles. Both studies are undertaken as group work within the undergraduate subject. The pedagogy of the projects is discussed in terms of the classical educational psychology literature concerning project-based learning, collaborative and guided learning and reflection. In terms of learning outcomes, the primary aim is to enable students to deliver a professional report as the final product, where physical model data are compared to ideal-fluid flow calculations and real-fluid flow analyses. Thus the students are exposed to a professional design approach involving a high level of expertise in fluid mechanics, with sufficient academic guidance to achieve carefully defined learning goals, while retaining sufficient flexibility for students to construct their own learning goals. The overall pedagogy is a blend of problem-based and project-based learning, which reflects academic research and professional practice. The assessment is a mix of peer-assessed oral presentations and written reports that aims to maximize student reflection and development. Student feedback indicated a strong motivation for courses that include a well-designed project component.

Multi-Media Fluid Mechanics

This multi-media product is intended to provide an interactive tool for teaching undergraduate fluid mechanics for students in engineering and the basic sciences. Funded by the National Science Foundation and written and prepared by an international group of experts, this CD-ROM includes experiments that demonstrate fluid mechanical phenomena, animations of important principles and concepts, virtual laboratories in which students acquire data from the images, interactive computational exercises in which parameters may be varied, and other descriptive and illuminating material on applications. The coverage is at the level of the Navier-Stokes Equations, but much of the material is accessible to lower level courses as well. The material is conveyed in an attractive and interactive way, with descriptive and developmental text accompanying all the videos and animations. The product is intended to complement any of the standard text books and uses notation and definitions that are standardized to the maximum extent possible. The material may be accessed randomly through a hyperlinked text, a search engine, a video library, and a glossary of terms.

Computer modeling of superimposed inviscid flows on a microcomputer

Complex flow patterns can be simulated in inviscid flow theory through the superposition of simple flows such as sinks, sources, and uniform flow. The resulting flows are valuable in modeling the flow of fluids at high Reynolds numbers and may be used to simulate the flow over airfoils, aircraft fuselages, ship hulls, and circular pipes in heat exchangers. A computer simulation program has been developed that models inviscid flow patterns and plots the resulting streamlines and equipotential lines on a microcomputer monitor. The program allows the user to superimpose doublets, sinks, sources, uniform flow, and vortices in any desired pattern. The code can also calculate and plot the inviscid velocity and pressure distribution at any point in the flow. A wide choice of singular 2-D flows can be superimposed with user-specified strengths, positions, and orientation angles. The program has been successfully used in undergraduate and graduate fluid mechanics courses and has been used to develop the pressure distributions around submerged structures.

Head recovery at submerged abrupt conduit outlets

The question of an abrupt expansion in a pipeline from one diameter to a larger diameter is a classical problem dealt with in most undergraduate fluid mechanics texts. A problem not dealt with, but which is far more common in practice, is the abrupt expansion at the terminal end of a pipe where the flow expands into an open channel downstream. It is often assumed that the entire velocity head for the pipe flow is lost. This is not necessarily true. In this paper, the experimental study of an abrupt expansion into an open channel is reported. Several different channel shapes are used in an attempt to determine shape effect, if any. It is concluded that the primary variable affecting the head loss is the ratio of the upstream to downstream flow area, called the area ratio. Key words: abrupt expansion, conduit outlet, head recovery, head loss, area ratio.