In this study, a hydrodynamic and a salinity transport models were developed for simulations of Sabine Lake water system located on the Texas-Louisiana border. The target simulation area includes several major water bodies, such as Sabine Lake, Sabine River, Sabine Pass, Sabine Neches Canal (Ship Channel), and part of Gulf Intracoastal Waterway (GIWW) and Sabine River Diversion Canal (SRDC). The SRDC supplies fresh water to the area industry, mainly petrochemical. High salinity in SRDC could significantly affect the daily production of the industry. Two-dimensional (2D) depth-averaged shallow water equation set and 2D depth-averaged salinity transport equation were used for developing the hydrodynamic and salinity transport numerical models in order to carry out the simulation. The major purposes of this study are to calibrate and validate hydrodynamic and salinity transport models in order to assess and predict the salinity in SRDC under severe weather conditions such as hurricane storm surges in future study. Measurement data from National Oceanic and Atmospheric Administration (NOAA) and United States Geological Survey (USGS) were used to calibrate the boundary conditions as well as to validate the model. Boundary conditions were calibrated at locations in Sabine Pass and in the north edge of the lake by using water–surface elevation data. Hydrodynamic model was validated at the USGS location using water–surface elevation data. Then, the simulation estimations of water surface level and salinity were compared at three locations, and the results show the accuracy of the validated model. Parallel computing was conducted in this study as well, and computational efficiency was compared.

The throat tap nozzle of the American Society of Mechanical Engineers performance test code (ASME PTC) 6 is widely used in engineering fields, and its discharge coefficient is normally estimated by an extrapolation in Reynolds number range higher than the order of 107. The purpose of this paper is to propose a new relation between the discharge coefficient of the throat tap nozzle and Reynolds number by a detailed analysis of the experimental data and the theoretical models, which can be applied to Reynolds numbers up to 1.5 × 107. The discharge coefficients are measured for several tap diameters in Reynolds numbers ranging from 2.4 × 105 to 1.4 × 107 using the high Reynolds number calibration rig of the National Metrology Institute of Japan (NMIJ). Experimental results show that the discharge coefficients depend on the tap diameter and the deviation between the experimental results and the reference curve of PTC 6 is 0.75% at maximum. New equations to estimate the discharge coefficient are developed based on the experimental results and the theoretical equations including the tap effects. The developed equations estimate the discharge coefficient of the present experimental data within 0.21%, and they are expected to estimate more accurately the discharge coefficient of the throat tap nozzle of PTC 6 than the reference curve of PTC 6.

Ambiguities, inconsistencies, and recommended interpretations of the commonly cited definition of validation for computational fluid dynamics codes/models are examined. It is shown that the definition-deduction approach is prone to misinterpretation, and that bottom-up descriptions rather than top-down legalistic definitions are to be preferred for science-based engineering and journal policies, though legalistic definitions are necessary for contracts.

This paper analyzes the operative characteristics of a three-hole cobra type probe especially designed to attain an angular range higher than 180 deg for planar turbulent flows. A new calibration and data reduction method are also introduced, discriminating three different zones inside the angular range of the calibration. This methodology improves the probe performance, extending its operative angular range from the typical ± 30 deg to ± 105 deg . In addition, the transmission of the uncertainty—from the pressure measurements to the flow variables—is estimated, showing reasonably low levels for the whole angular range. Furthermore, the sensibility of the probe calibration to the Reynolds number and the pitch angle is considered, and the influence of the turbulence level is outlined. Regarding these factors, the probe precision in the extended angular range is found to be similar to that of the traditional range. Finally, the probe is tested in a flow field with large variations of the incidence angle, and the results obtained with the new method are compared to those given by the traditional calibration.

State-of-the art dimensional metrology was used to measure the throat diameter and throat curvature of nine critical flow venturis (CFVs) with nominal throat diameters ranging from 5 mm to 25 mm . The throat curvature was used in calculating the theoretical discharge coefficients, while the throat diameter was used in computing the experimental discharge coefficients. The nine CFVs were calibrated in dry air using two NIST primary flow standards with expanded uncertainties of 0.05% and 0.09%, respectively. The calibration data span a Reynolds number range from 7.2 × 10 4 to 2.5 × 10 6 , including laminar, transition, and turbulent flow regimes. By correcting for both the throat diameter and curvature, the agreement between predicted and measured discharge coefficients was less than 0.17% in the turbulent regime and less than 0.07% in the laminar regime.

Laboratory experiments and numerical simulations are performed to determine the accuracy and reproducibility of the falling-ball test for viscosity determination in Newtonian fluids. The results explore the wall and end effects of the containing cylinder and other possible sources that affect the accuracy and reproducibility of the falling ball tests. A formal error analysis of the falling-ball method, an evaluation of the relative merits of calibration and individual measurements, and an analysis of reproducibility in the falling-ball test are performed. Recommendations based on this study for improving both the accuracy and reproducibility of the falling-ball test are presented.

This investigation analyzes the calibration nonlinearity of the ball-in-vortex flow-meter, designed to work on the principle of a rotating sphere in and due to a vortex flow. The comparison of this flow-meter reading with the standard flow-meter indicates the existence of different calibration regimes, bifurcated by a sharp change in slope of the calibration curve. Based on the governing mechanics of this flow-meter, this paper explains this nonlinearity, and proposes its mathematical form. In particular, the bifurcation in calibration characteristics is attributed to the change in the surface contact frictional force, due to translation of the ball. The mathematical model captures the various calibration regimes associated with this translation, from one plane of rotation in the flow-meter to another, or from one periphery to another. Thus, calibration nonlinearity of this flow-meter can be fully comprehended through its governing mechanics, and harnessed for flow measurement.

An ultrasonic instrument to measure the density of a liquid or slurry through a stainless steel pipeline wall is described. By using multiple reflections of the ultrasound within the stainless steel wall, the acoustic impedance (defined as the product of the density of the liquid and the velocity of sound in the liquid) is determined. Thus, the wall is part of the measurement system. The density is obtained by coupling the acoustic impedance measurement with a velocity of sound measurement. By basing the measurement on multiple reflections, instrument sensitivity is increased by the power of the reflection coefficient. The measurement method is self-calibrating because the measurement of the acoustic impedance is independent of changes in the pulser voltage. Data are presented over a range of pulser voltages for two wall thicknesses. These results can be applied to develop an ultrasonic sensor that (1) can be attached permanently to a pipeline wall, possibly as a spool piece inserted into the line or (2) can clamp onto an existing pipeline wall and be movable to another location. The self-calibrating feature is very important because the signal strength is sensitive to the pressure on the clamp-on sensor. A sensor for immersion into a tank could also be developed.

A new pressure, volume, temperature, and time (PVTt) primary gas flow standard for calibrating flowmeters has an expanded uncertainty k = 2 of between 0.02% and 0.05%. The standard diverts a steady flow into a collection tank of known volume during a measured time interval. The standard spans the flow range of 1 slm 1 to 2000 slm using two collection tanks (34 L and 677 L) and two flow diversion systems. We describe the novel features of the standard and analyze its uncertainty. The thermostatted collection tank allows determination of the average gas temperature to 7 mK (0.0023%) within an equilibration time of 20 min. We developed a mass cancellation procedure that reduced the uncertainty contributions from the inventory volume to 0.017% at the highest flow rate. Flows were independently measured throughout the overlapping flow range of the two systems and they agreed within 0.015 %. The larger collection system was evaluated at high flows by comparing single and double diversions; the maximum difference was 0.0075%.

Calibration of multihole aerodynamic pressure probe is a compulsory and important step in applying this kind of probe. This paper presents a new neural-network-based method for the calibration of such probe. A new type of evolutionary algorithm, i.e., differential evolution (DE), which is known as one of the most promising novel evolutionary algorithms, is proposed and applied to the training of the neural networks, which is then used to calibrate a multihole probe in the study. Based on the measured probe’s calibration data, a set of multilayered feed-forward neural networks is trained with those data by a modified differential evolution algorithm. The aim of the training is to establish the mapping relations between the port pressures of the probe being calibrated and the properties of the measured flow field. The proposed DE method is illustrated and tested by a real case of calibrating a five-hole probe. The results of numerical simulations show that the new method is feasible and effective.

Two data-reduction methods were compared for the calibration of a seven-hole conical pressure probe in incompressible flow. The polynomial curve-fit method of Gallington and the direct-interpolation method of Zilliac were applied to the same set of calibration data, for a range of calibration grid spacings. The results showed that the choice of data-reduction method and the choice of calibration grid spacing each have an influence on the measurement uncertainty. At high flow angles, greater than 30 deg, where flow may separate from the leeward side of the probe, the direct-interpolation method was preferable. At low flow angles, less than 30 deg, where flow remains attached about the probe, neither data-reduction method had any advantage. For both methods, a calibration grid with a maximum interval of 10 deg was recommended. The Reynolds-number sensitivity of the probe began at Re=5000, based on probe diameter, and was independent of the data-reduction method or calibration grid spacing.

This paper describes recent advances in the development of a temperature measurement methodology based on phosphorescence of a tracer molecule in a liquid. The methodology represents an extension of molecular tagging velocimetry (MTV). MTV is a laser-based technique of obtaining spatially resolved fluid velocity profiles. The methodology has the potential of providing spatially resolved simultaneous measurements of velocity and temperature data over a planar domain. Presently, a method of obtaining temperatures over a range of 30°C with a typical uncertainty of ±1.0–1.5°C has been developed. Recent progress has resulted in a method of generating robust calibration curves for use in subsequent temperature measurements. A discussion of the experimental methodology, calibration curve development, and error analysis is presented. Finally, simultaneous temperature and velocity profile measurements using the method are demonstrated under dynamic conditions.

The velocity field in the vicinity of a target surface with a turbulent slot jet impinging normally on it is examined. The impingement region is confined by means of a confinement plate that is flush with the slot and parallel to the impingement plate. The distance H of the impingement wall from the slot is varied from 2 to 9.2 slot widths. Jet Reynolds numbers (based on slot width B ) of 10,000–30,000 are considered. Mean velocity and root mean square velocity measurements are carried out using hot-wire anemometry. A boundary layer probe is utilized in order to obtain measurements at a wall distance as close as 110 microns 0.0028 B . This corresponds to a distance of approximately y + ∼ 2 - 4 in wall units and is found to be adequate in order to permit an estimate of wall shear under most conditions. The problems of hot wire interference with the wall and calibration at low velocities are solved by calibrating the probe in a known Blasius flow. With the exception of the stagnation region where shear could not be evaluated, it is found that velocity profiles follow a linear behavior in the viscous sublayer everywhere along the wall. Results indicate that the peak in normal stress occurs at y / B ∼ 0.025 to 0.04 at a distance six to eight jet widths away from the jet-axis.

This work presents the development of a data reduction algorithm for non-nulling, multihole pressure probes in compressible, subsonic flowfields. The algorithm is able to reduce data from any 5- or 7-hole probe and generate very accurate predictions of the velocity magnitude and direction, total and static pressures, Mach and Reynolds number and fluid properties like the density and viscosity. The algorithm utilizes a database of calibration data and a local least-squares interpolation technique. It has been tested on four novel miniature 7-hole probes that have been calibrated at NASA Langley Flow Modeling and Control Branch for the entire subsonic regime. Each of the probes had a conical tip with diameter of 1.65 mm. Excellent prediction capabilities are demonstrated with maximum errors in angle prediction less than 0.6 degrees and maximum errors in velocity prediction less than 1 percent, both with 99 percent confidence.

This paper describes a novel in-line sensor that measures the magnitude and direction of gas flow in a tube. The sensor possesses a unique set of performance characteristics: low detection limit, little resistance to flow, and directional sensitivity. The sensor consists of two hot wire anemometers mounted in a U-shaped tube. Differences in the signals between the two hot wires under low velocity conditions are used to determine the direction of the flow. Calibration curves of flow rate versus measured velocity are used to determine the magnitude of the flow. The sensor has applications in systems that are characterized by naturally driven oscillating flows. [S0098-2202(00)02701-2]