CIVL 321 LABORATORY Spring 2024 Laboratory Group Report Format Organization of Report: I. Title page (see sample) II. Laboratory description handout III. Results table IV. Graphs* V. Answers to questions* VI. Appendix a. Raw data sheet b. Complete set of sample calculations * as requested in handout General Instructions: 1) Report must be complete, neat, and legible. 2) All pages must be 81/2" x 11", and bound/stapled together in the correct order. The name of the person who prepared each page (except the Title page) must appear in the lower right corner. 3) All report content must be typed, with the exceptions of: 1) The sample calculations. These can be handwritten. 2) The raw data information may also be handwritten on the data sheet. 4) Results tables must be prepared in a spreadsheet program or equivalent with appropriate headings. The dimensional units for all displayed results must be clearly indicated. 5) The sample calculations must take one set of data and show each calculation required to generate the Results table, produce the graphs, and answer the questions (if applicable). All unit conversions must be shown and all calculations must carry at least three (3) significant digits. Sample calculations may be handwritten in pen or pencil – but they must be extremely neat. 6) Graphs must be prepared in a graphing program such as Excel or Matlab and follow accepted engineering practice as indicated below and shown in the example on the following page: a. b. C. d. e. f. g. Each graph must contain a meaningful title that describes its content. Coordinate axes must be appropriately scaled and have major gridlines. Coordinate axes must be labeled with words, symbols (if applicable), and proper units. Experimental data should appear as marker symbols without lines. If requested, x- and y- error bars should be indicated on each data point. Theoretical curves should appear as smooth lines without marker symbols. They should be clearly labeled to indicate they are theoretical results. Least-square curve fits (Trendlines) must be accompanied by the curve fit equation and R² value with at least three (3) significant digits shown. Multiple data sets on the same graph should be clearly identified through the use of labeling or a legend. Grading: The laboratory experiments reports are expected to be neat, succinct, and well written. Unless otherwise stated, all reports must be submitted at the beginning of the laboratory period following the performance of the experiment. Late reports will not be accepted. All students who contribute to the experiment and report will receive the same grade. Sample Title page Specify lab by group number, day, and time. Names listed in alphabetical order by last name Drag Coefficient Measurement of an Ogive-shaped Projectile in Subsonic Flow Drawdown (m) Sample Graphs & Tables Graphs have meaningful title, axis labels with proper units. Note that the titles tell me more than just "Drawdown vs. time", which I should know already just by looking at the axis labels. Clear legend, data as markers, theoretical as line, and at least 3 significant digits in regression equations. Tables have clear headings for each column with the dimensional units clearly specified. Values are listed with appropriate number of significant digits. 2 Line fit to drawdown at 80 m from well using log transformed time (first 4 data points removed) 1.8 1.6 drawdown (m) 1.4 1.2 1 0.8 0.6 drawdown (obs) Linear (drawdown (obs)) y=0.5912x+ 0.0865 R² = 0.9988 0.4 0.2 0 0 1 2 3 log time (min) Drawdown at 80 m from pumping well Time (min) Drawdown (meters) 2 1.8 0.5 0.16 1.6 1 0.18 2 1.4 0.24 3 0.27 1.2 4 0.47 1 Drawdown (obs) 5 0.50 0.8 Theis solution 7 0.57 0.6 10 0.68 20 0.84 0.4 30 0.96 0.2 50 1.06 0 100 1.29 0 200 400 600 800 1000 1200 Time (min) 200 1.46 500 1.68 1000 1.86/n CIVL 321 LABORATORY Spring 2023 Objective: Fluid Mechanics Lab #6 Velocity Profile in an Open Channel The student is to measure the velocity profile in an open channel flow using an acoustic Doppler velocimeter (ADV). The total volume of discharge is determined by numerical integration and compared to a calibrated orifice meter measurement. The experiment is designed to introduce the student to acoustic Doppler velocimetry, the methods and problems of measuring non-uniform velocity profiles, and computation of volumetric flow from velocity measurements. Procedure: 1. Establish the coordinate system using the bottom and the left side (looking downstream) as the axes. Refer to the prepared data sheet. Note that the channel width is 2.0 ft. 2. Establish a steady flow in the flume with the help of the instructor. If there is a hydraulic jump in the channel, the measurement station should be at least 10 feet downstream of the hydraulic jump. 2. Attach the Comark C9500 differential pressure gage to the orifice meter in the pipe supplying the flume. Record the pressure drop across the orifice plate. Be sure to take at least 3 readings and average them. 5. Using the point gage, determine the depth of the flow. Then determine the vertical grid spacing that your group will use to measure the velocity profiles in the channel. Note that there will be five locations in the vertical (z) direction, including the free surface. The first location is 0.10 feet from the bottom. 6. Measure the velocity in the x-direction at the predetermined grid locations with the ADV using a 40 second average. Note that the measurement location is 10 cm from transmitter (yellow, circular face of the probe), so you will need to rotate the probe 180° when measuring near the wall. Use the manual traversing mechanism and scales to set the horizontal and vertical positions. Measure the free surface velocities by timing the travel a small floating object. Material to be Included in Report in Addition to Normal Requirements: 1. Using the following equation, compute the volume discharge in the flume: Q=0.50*AP0.5 (1) Where Q is in cfs and AP is in inches of mercury. Compute the average velocity, V, in the flume from the known cross sectional area at the measurement station. 2. Transpose the measured velocity grid to an Excel spreadsheet. Use Excel to calculate the average velocity within each rectangle defined by the grid points, the cross sectional area of each grid rectangle, the volume flow rate (discharge) through each grid rectangle, and the total channel discharge in cfs. Also calculate the total area and check with the known channel cross sectional area. 3. On a single graph, plot the vertical velocity profile for each value of y. 4. One a single graph, plot the horizontal velocity profile for each value of z. 5. Plot the velocity profile in Excel using a 2-D surface, shaded contour type chart on a separate sheet. Use at least eight (8) velocity increments*. 6. Compare the discharge calculated by numerical integration with the orifice meter measurement. Compute the % error based upon the orifice meter measurement. Is the discharge measured with the velocity probe within the uncertainty of the measured value from the orifice plate? 1 Scanned with CamScanner DATA SHEET for Velocity Profile in an Open Channel Orifice meter pressure gauge reading 1: AP = Orifice meter pressure gauge reading 2: AP = Orifice meter pressure gauge reading 3: AP = Average pressure difference: AP = Volume flow rate, Q = 0.50 *AP0.5 (AP in inches of Hg) = Velocity Measurements with the Sontek Acoustic Doppler Velocimeter: cfs Raw y yin ft- 0.0 0.15 0.3 0.6 1.0 1.4 1.7 1.85 2.0 Raw z z in ft Free 0.00 0.00 surface 0.00 0.00 0.00 0.00 0.00 0.00 0.1 0.00 0.00 0.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Notes: 1. Measurement grid is referenced to a downstream view. 2. Free surface velocities are measured by timing a small floating object with a stopwatch. Time the float over a distance of four (4) feet, centered about the measurement station. 0.25' 0.1' 0 0.625 0.25 1.5 (1.0) 1.375 0.55 The diagram shows a section from the bottom left corner of (1.8) the flume. Values in circles are measured velocities from the ADV. The measured values form a grid as indicated by lines connecting the circles. Average the 4 neighboring values in a grid box to calculate the average velocity within the grid box, as indicated by the arrows. Use the vertical and horizontal dimensions of the grid box to calculate the area of the grid box. (1.2) 0.0' 0 0 0.0' 0.15' 0.30 2 23 Scanned with CamScanner ter I