As the angle increases, the target speed erroneously decreases, as Table 1 below shows. Honestly, most people who gauge streams, including the USGS don't continuously measure velocity at all. “The device is a more efficient and inexpensive way to measure evaporation when compared with existing methods,” Bengaluru-based IISc said in a statement on Friday. This is a phenomenon called the cosine effect. A radar device for measuring the surface velocity of water moving in a horizontal plane in which the radar device is positioned above or below the horizontal plane. Accelerometers can detect a change in tilt because they can measure and account for the Earth's gravity. The equation is used to measure flow in locations where the construction of a hydraulic structure (flume or weir) is impractical. POEM is a Pressure Operated Electronic Meter, with no moving parts, developed for gauging flooded rivers with flow rates up to 10 m/sec. Staff gages and float-operated units are the simplest devices used for this purpose. While technology has changed over the years, we've still achieved a high level of standardization. Others are more suitable for monitoring water flow in pipes. They are rugged, easy to use and suitable for flood gauging. Thus, the speed calculation must compensate for the horizontal angle. This results in an automatically corrected measured velocity being displayed on the radar device. A pitot tube is a simple device meant for measuring the velocity of a liquid at any point. Often the device is used in hazardous conditions, such as flooding, so using the radar device above the water minimizes the risk to the operator. In all cases, the radar device is elevated above the water, so the vertical angle must be compensated for. The speed of the rotating wheel indicates the velocity of the current. The law of electromagnetic induction is also utilized, which takes the water ﬂow as a conductor to measure the ﬂow velocity. Calculate Velocity Of Air In The Duct (Specific Gravity Of Oil= 0.7 And, Density Of Water Is 1000 Kg/m3) Not all flow measuring devices ... wood, or fiberglass and can measure water over a wide variety of flow ranges. FIG. Swoffer water flow meters are designed to measure velocity in any application from streams and rivers to storm water and sewage. Many factors can generate currents, such as gravitational forces, rotation of the earth, wind, water conditions gradients and/or geographical landscapes. This Acoustic Doppler Current Profiler (ADCP) can accurately measure the velocity of rivers, streams, estuaries, channels, ports and harbours, across a channel up to 300 meters wide. The water velocity probe consists of a protected water turbo prop positive displacement sensor coupled to an expandable probe handle with a digital readout display. It has a tail fin, to allow cable gauging, so can't operate in water as shallow as the Pygmy. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). In the past, entry of the vertical angle was estimated by the operator and calculated manually or the information was manually entered into the radar device and the software would calculate the cosine correction factor. While the invention has been described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. At the same time that the microprocessor is receiving a reading from the y-axis sensor, Turning to FIG. The greater the tilt angle, the greater the effect of gravity on one of the sensors. Larger flumes are constructed on site, while smaller flumes can be ... can operate in flat ditches, are relatively insensitive to approach velocity, and are self-cleaning due to the high velocity of water passing through. If the indicated speed on the radar gun is 10 feet per second and no cosine correction is made, then the actual speed of the water is 11.17 feet per second. The reflected signal frequency shifts by an amount proportional to the speed of the target. “The device is a more efficient and inexpensive way to measure evaporation when compared with existing methods,” Bengaluru-based IISc said in a statement on Friday. The liquid may be entirely open to the atmosphere, or may be contained within a closed pipe that is not full of liquid and only open to the atmosphere at the installation point of the flowmeter itself. Each sensor has a frequency output from which its angle position is determined. Read about NIWA's current meter calibration service and flow stations in this article. When This Pitot Static Tube Is Placed In The Flow, 50mm Difference In Manometric Fluid Is Noted. There are many different types of meters by the most common is the Pygmy meter, the vortex meter, the flow probe, and the current meter: They are briefly described below. When taking readings of moving water, such as rivers or streams, the radar gun is generally positioned above the stream, on a bridge, or adjacent to the stream, on a riverbank. The USGS has been doing this since 1889, when it established its first stream gage on the Rio Grande River in New Mexico to determine how much water was availabl… Water flow instruments range from small acoustic doppler current profiling devices or small prop type meters for measuring very low flows in small streams, up to NIWA's flood-gauging POEM. The radar gun reads the frequency data from the tilt sensors, and the computer software uses this in calculating the cosine corrected angle of the angle formed by the radar device and the point where the velocity is measured. 3 is an electrical schematic diagram of the accelerometer used to determine tilt angle and how it is connected to the radar device's microprocessor. The formula utilizes the cross-sectional average velocity, hydraulic radius, roughness coefficient, and the slope of the channel. 2 is a schematic view of a typical application of the radar gun measuring the surface water velocity of a moving body of water. Flow Stations - These are usually a permanent structure located at a carefully selected, or constructed, stable site. When the antenna transmits the beam of radio waves, the beam forms an elliptical pattern onto the target area. 7.72). When the beam strikes the target, a small amount of energy from the beam is reflected back to the antenna in the radar device. When used in measuring the volume of water passing though the water in a water meter, or the speed of the water passing through a flow meter, it is actually measuring the sound as it bounces off of bubbles, dirt or impurities in the water. Instead, it must be calculated in a process known as stream gaging. This is known as the Doppler effect. For water flowing in a pipe under steady-state conditions (i.e., not changing over time), continuitymeans the water that flows into one end of a pipe must flow out of the other end. This small bucket wheel current meter has a very low starting velocity and no tail fin, so is ideal for measuring very low flows in shallow water. a processor mounted in the radar gun to receive the output signal. An accelerometer is a sensor that converts acceleration from motion or gravity to an electrical signal. The conversion is usually done with a rating derived from gauging the cross section of the open channel beside the station, or using the relationship associated with a weir constructed downstream. a radar gun with means for generating a signal at a predetermined frequency directed at an object, the radar gun oriented at a vertical angle with respect to the object. Simultaneously the other sensor displaces a smaller angle and the effect of gravity on the other sensor is less. primary radar systems; Analogous systems, Systems of measurement based on relative movement of target, Velocity or trajectory determination systems; Sense-of-movement determination systems, Velocity or trajectory determination systems; Sense-of-movement determination systems processing the video signal in order to evaluate or display the velocity value, ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SMITH, KIMBLE J.;JANSON, SCOTT D.;SMITH, KEVIN T.;REEL/FRAME:012183/0456;SIGNING DATES FROM 20010909 TO 20010911, ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION, Simulating a radar signal reflected from a moving target, Method and Apparatus for Acquiring Local Position and Overlaying Information, Radar speed measuring device and method based on angle compensation, Device for measuring the frequency of vibrations on a tight drive belt, and method for performing the vibration frequency measurement, Method for estimating flow by means of radar wave flow meter, The device measured for the frequency of vibration of driving belt being tensioned and for performing the method that frequency of vibration is measured, Device for measuring the frequency of vibration in a tensioned drive belt and method for performing vibration frequency measurement, Device for measuring the frequency of vibrations on a tight drive belt and a method for carrying out the vibration frequency measurement, Gyro sensor module and angular velocity detection method, Method and system for determining position and orientation of an object, Surveying and position measuring instrument with a fan-shapped light beam, Level, angle and distance measuring device, Monitor device that measures and displays the flight characteristics of sports objects, Yield monitoring apparatus, systems, and methods, Laser sensor capable of measuring distance, velocity, and acceleration, Low cost 2D position measurement system and method, Solid state orientation sensor with 360 degree measurement capability, System for determining performance characteristics of a golf swing, Handheld optical distance measurement device, Handheld laser light detector with height correction, using a GPS receiver to provide two-dimensional position data, System, method, device and computer code product for improving the readability of an electronic compass, Gradient sensor and method of using the same, Remote attitude and position indicating system, Method and apparatus to determine the wind speed and direction experienced by a wind turbine, Method of adjusting monitor axis of optical sensors, Golfer's wind indicator and club selection assistance device, Method and apparatus to determine object striking instrument movement conditions, System for using a 2-axis magnetic sensor for a 3-axis compass solution, Information on status: application discontinuation. Turning first to FIG. With the mobile measuring device RP-30 (Radar Profiler) a surface velocity profile from rivers and channels is created and together with the data of the river cross-section and water level the discharge is determined. means for correcting the calculated velocity to a corrected calculated velocity of the object if the radar device is positioned at the vertical angle with respect to the object. The change in … These consist of a primary device, transducer, and flow transmitter. Another advantage of taking measurements above the water is that waterproof instruments are not required. Read about how a POEM was used to gauge the flow of water entering the Lake Pukaki canal on the Waitaki hydroelectric scheme POEM has no moving parts and, in addition to measuring flow up to 10m/s, can simultaneously provide useful information about turbulence. With this device you are able to measure the velocity of a free flowing stream. 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