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J. Sterling Jones Hydraulics Research Laboratory

 

HYDRAULICS LABORATORY PHYSICAL MODELING

Dual-Drive Wave Making Tube

The photo shows the Dual-Drive Wave Making Tube with the control electronics.

The wave making tube.		 The photo shows a closeup of the testing chamber of the Dual-Drive Wave Making Tube. It is made of clear material to allow observation of the erosion process as well as potential particle image velocimetry measurement. The chamber has an opening for the installation of the force sensor.

Test chamber of the wave making tube.

 

Description:
Scour development is complicated especially by the presence of large-scale turbulence structures. The roles that such turbulence structures play in pier scour have been only partially appreciated. Turbulence structures, together with local flow convergence/contractions around the broad fronts and flanks of piers or between piles of complex pier configurations, are erosive flow mechanisms of primary importance. This device applies various turbulent/dynamic hydraulic loading conditions to a range of different cohesive soils and measures the soil erosion response. The turbulent hydraulic loading is characterized by fluctuating/oscillating shear and normal forces. The Dual-Drive Wave Making Tube uses dual pistons in a tube to oscillate a water body over soil samples. The device generates turbulent/dynamic hydraulic loading conditions to a range of different cohesive soils. The soil samples in the test section are mounted on a sensor that simultaneously measures shear stresses and vertical forces. It is automated with LabVIEW codes and can produce programmed cyclic flow conditions.

 

In Situ Scour Testing Device

In this picture, the first version of the ISDT device is shown. The device was built in a water tank partially filled with soil/sand to simulate real river conditions. The vertical movable device is supported and pushed downwards by two screw jacks. The black flexible hose connection at the left side is the inlet to the device. This flow goes through a labyrinth inside the device designed to eliminate the jet effect from the inlet. In the testing area, the flow creates a reasonably uniform horizontal shear stress on the bed material. The eroded soil is removed by the water flow leaving the device. An inductive distance sensor (LVDT) measures the height of the channel allowing the control system to maintain a constant area between device and soil. The vertical movement during a specific amount of time represents the erosion rate of tested soil. The alternative design of the ISDT consists of a cylindrical body. Two independent rotary parts are mounted inside this body. The outer part is a hollow bronze auger. The inner part, with a yellow impeller at the bottom, rotates at high speed. This rotation causes a water flow similar to the impeller pump. The soil material below the device is entrained by the shear stress. In the middle of the impeller, an inductive distance sensor (LVDT) measures the gap between the device and the soil to allow the control system to maintain a constant distance. As the erosion goes on, the impeller moves along the eroded sediment bed. To prevent the surrounding soil from filling up the hole, the bronze auger continues slowly excavating the material outside the erosion
Concept 1: The U-ISTD was developed in the lab to demonstrate a concept of producing horizontal shear stress for in situ erosion testing. It features a U-shaped channel that creates steady horizontal flow near the flume bed. Concept 2: The I-ISTD uses a revolving impeller housed in a hollow auger to exert bed shear. The eroded material is removed with flow through internal tubing. The auger excavates the stream bed to allow for sublevel testing.
  The C-ISTD in the picture presents an early version for proof of concept. The surrounding glass tube provides visual access during the testing. The erosion head consists of two blue spacers and a clear acrylic body between them. The spacers maintain a small gap between tube and erosion head. During a test, water runs through the gap to the perimeter of the bottom of the head. The only drain in the system is a small hole in the middle of the head. Between the perimeter and the center of the bottom of the erosion head is an erosion chamber shaped to allow a uniform concentric flow. The water running towards the drain produces an evenly distributed shear stress and entrains the sediment. A certain distance is maintained between the bottom of the erosion head and the soil. When erosion occurs, the movement rate of the erosion head represents the erosion rate. This ensures an optimal shape for the erosion chamber.

Concept 3: the C-ISTD, named for its cylindrical-shaped erosion head, produces shear stress by radial flow in the erosion chamber at the bottom of the cylindrical erosion head (between the two blue disks in the photo).		  

 

Description:
This study develops a scour testing field device (in situ scour testing device) to determine the erodibility of soils around bridge foundations. An effective in situ scour testing device could more accurately define the scour potential for a given set of hydraulic design conditions. Such a field device could provide assistance on a project-by-project basis or in general design methodology.

 

Force Balance Flume

The picture shows the Force Balance Flume, which is 45 feet long and 14 inches wide, viewed from the downstream end. The picture also shows the flap gate to control the water level in the flume.

View of the Force Balance Flume.		 The picture shows the Force Balance Tower. A model of a bridge deck is mounted inside the Force Balance Tower and lowered into the flume.

View of the Force Balance Tower.

 

Description:
The Force Balance Flume is 45 feet long and 14 inches wide. In this configuration, a discharge rate of over 900 gallons per minute can be achieved.  It has a force balance device that is used to determine lift and drag coefficients for inundated bridge decks. This flume can be easily modified into a wave channel by mounting a paddle to the existing two-dimensional shaker while the flume is filled with still water. It has an apparatus for measuring the movement of a bridge deck model using a motion capturing technique and various sensors while being hit by waves. The flume utilizes a two-axis robot to measure the velocity distribution using an Acoustic Doppler Velocimeter probe.

 

Fish Passage Culvert Flume

The picture shows the fish passage culvert flume from the downstream end. The upper part of the flume is tiltable. The water falls over a flap gate into a tank under the flume. The picture shows the channel of the fish passage culvert flume. A corrugated pipe is installed inside the channel and water runs through it.
View of the fish passage culvert flume. View of the corrugated pipe inside the fish passage culvert flume.

 

Description:
The fish passage culvert flume is 29 feet long and 18 inches wide. In this configuration, a discharge of 700 gallons per minute can be achieved. The flume is tiltable up to 2.6 degrees. Different sections of a corrugated pipe can be inserted into the flume to measure and visualize the flow distribution at any cross section. The flume utilizes a 2-axis robot to measure the velocity distribution using an ADV probe. Two-dimensional, three-component Particle Image Velocimetry (PIV) can be performed in this flume.

 

Tilting Flume

The picture shows the tilting flume from the downstream end. In the middle of the flume there is a recess filled with sand for scour experiments.

View of the tilting flume.		 The picture shows the carriage from the tilting flume. The carriage is a three-axis robot resting on two rails on top of the tilting flume; it has an ADV probe and a laser distance sensor mounted to it.

View of the tilting flume’s carriage system.

 

Description:
The tilting flume is 70 feet long and 6 feet wide and has a sediment recess for highway-related scour experiments. The maximum discharge of this flume is 3,000 gallons per minute. The flume utilizes a three-axis carriage to measure the velocity distribution using an Acoustic Doppler Velocimeter probe and to map any scouring that has occurred in the sediment recess using a laser distance sensor.

 

Miniculvert Flume

The picture shows the miniculvert flume from the downstream end. Stand pipes are mounted on the right side along the flume.

View of the miniculvert flume.		 The picture shows the stand pipes in the culvert section. Optical pressure measurement sensors are mounted on the stand pipes to measure the pressure inside the culvert.

View of the optical pressure measurement sensors.

 

Description:
The miniculvert is 12 feet long and 10 inches wide. It has an open flume section that leads into a culvert. Stand pipes are distributed along the flume to measure the energy and hydraulics grade line along the passage from the open channel into the culvert. Optical pressure measurement (OPM) sensors are mounted to the stand pipes to measure the water pressure automatically. The culvert section can be replaced with a special culvert section that allows performing two-dimensional, three-component Particle Image Velocimetry (PIV).

 

Ex Situ Scour Testing Device

The picture shows the ex situ testing device from a side view. A belt drive is located in a top box with the test channel underneath it.

View of the ex situ device.		 The picture shows the shear stress sensor mounted at the bottom of the ex situ testing device. A soil sample placed inside of the sensor is pushed through the bottom of the flume into the test channel.

The shear stress sensor mounted under the ex situ device

 

Description:
The ex situ scour testing device is 36 inches long and 14 inches wide. A special velocity distribution in the test section can be achieved within a 20-millimeter-gap through the combination of flow created by a moving belt and flow generated by a pump. In this configuration, a velocity of 6 meters per second can be achieved. Soil samples are mounted on shear and normal force sensors while pushed into the flow to account for the steady abrasion that occurs. Two-dimensional, two-component Particle Image Velocimetry can be performed in this flume.

 

Particle Image Velocimetry (PIV) Flume

  The picture shows the Particle Image Velocimetry flume from the upstream end. The picture also shows how the flume utilizes a vertical and horizontal trumpet shaped inlet to create a uniform flow.

View at the Particle Image Velocimetry flume.		  

 

Description:
The Particle Image Velocimetry (PIV) flume is 25 feet long and 12 inches wide and has a discharge rate of over 200 gallons per minute. This flume is mainly used to measure and visualize flow along the cross section of bridge models using two-dimensional, two-component PIV. If necessary, a custom-shaped Plexiglas® sheet can be anchored at the bottom of the flume to simulate a preformed scour hole.

 

J. Sterling Jones Hydraulics Research Laboratory Particle Image Velocimetry (PIV) System

The picture shows a model of a bridge deck is submerged in water. A cross section of the bridge deck is illuminated by a laser. Particles within this light sheet are reflecting the light. The picture shows a 2D-3C PIV setup. It shows two cameras mounted on top of the flume in an angle towards a cross section of the flume. From the front, a laser illuminates the cross section with a light sheet. Particles in the flow crossing the light sheet are reflecting the laser light.
View of an illuminated cross section of a submerged bridge deck while performing 2D-2C PIV. View of 2D-3C PIV experimental setup.

 

Description:
The laboratory has the ability to perform two-dimensional, two-component (2D-2C) and two-dimensional, three-component (2D-3C) Particle Image Velocimetry (PIV) in numerous flumes. The PIV system can record images at 15 Hz using a120 mJ YAG Laser and cameras with 960-by-960 pixels resolution.

 

Enhanced Particle Image Velocimetry (PIV)

  The picture shows on the left the new dual 10kHz high-speed laser. The unit on the right is a chiller that keeps the laser coolant at a constant temperature of 26 degrees Celsius. The unit in the back provides the voltage and trigger impulses for the laser.

A new PIV system that is capable of time-resolving PIV measurements is being developed.		  

 

Description:
The new Particle Image Velocimetry (PIV) system allows data acquisition rates of up to 500Hz with two cameras at full resolution. This allows high resolution recordings/capturing of the complicated flow patterns around bridge foundations. The new time-resolved PIV system is primarily used to compare flow fields with computational fluid dynamics (CFD) models and to calibrate CFD models.