Static Performance of Power Augmented
Ram Platform
Eliana Rodriguez (Advisor: Dr. Matveev)
REU Site: Introduction to Multiscale Engineering
School of Mechanical and Materials Engineering
• There are several advantages of PAR vehicles as high-payload
transports such as:
• The independent variables were spatial positions of the pitot tube.
30 Degree
0 Degree
30 Degree
60 Degree
90 Degree
60 Degree
90 Degree
2/5
3/10
1/5
1/10
- 1/10 0
5
- 1/5
• The third experiment that was conducted similar to the first experiment,
but instead of a straight platform, a slanted platform positioned at five
degrees to a horizontal plane was used.
• As before, an air nozzle and a platform with a flap were placed inside a
rectangular tank filled with water.
20
0
x (in)
5
10
x (in)
• The only independent variable of this experiment was water level.
30
1 inch from the air jet
3 inches from the air jet
5 inches from the air jet
25
20
15
Fig. 12 Recordings taken from
3 inches from the board.
10
5
0
-20
Objective
-5 0
20
40
Position of the tube
• In the slanted platform experiment, there was higher pressure build-up
under the slanted platform compared to the straight platform. This is
believed to be due to more pronounced stagnation of air flow.
• The goal of this research is to help achieve a better understanding
about aero-hydrodynamic phenomena in PAR systems.
Experimental Methods and Materials
Water Deformation
0.5
• The first experiment simulates a static PAR vehicle with the air jet
representing a jet engine and the plate with a flap representing the
vehicle’s platform.
0.4
Results
• In the jet impingement experiment, it was found that the highest static
pressure under the platform and the most significant water level
depression were generated when the flap closed the exit from the
under-platform channel.
Water Deformation
Fig. 3 Schematic of the jet impingement experiment.
0.30
Air Pressure
0 Degree
30 Degree
60 Degree
90 Degree
0.10
0.00
-0.10
-0.20
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
30 Degree
90 Degree
0
5
10
x (in)
15
20
0.3
0.2
0.3
0.2
0.1
0.1
0
0
0
5
10
15
20
0
5
10
x (in)
x (in)
Fig. 13 & 14 Recordings at the static water level set at 1½ inches from the platform
and the air jet set at nominal flow rate of 150 SCFH. SCFH
Conclusion
• Measured water surface deformations and air pressure distributions under
the PAR platform can be used for designing PAR vehicles and validating
mathematical models.
• Unsteady regimes (with occurrence of waves and spray) were noticed in
the experiments with flap positions at 0 and 30 degrees. Further
investigations of such conditions using time-resolved measurements are
warranted.
inH2O
h (in)
0.20
0 Degree
60 Degree
inH2O
h (in)
Fig. 7 The slanted platform experiment.
Air Pressure
0.5
0.4
• With open flap positions, the water in the tank became highly unsteady,
and oscillatory wave patterns were developed.
Fig. 4 The jet impingement experiment.
15
• When the pitot-tube was placed at three or five inches from the air jet, the
jet thickness expanded.
Velocity Distribution Experiment
-40
• The independent variables in this experiment included the static
water level, platform flap angle, and jet airflow rate.
10
• In the velocity distribution experiment, when the pitot-tube was placed at
1 inch from the nozzle, the measured velocity profile showed a narrow jet.
Fig. 6 Velocity measurement experiment.
• An air nozzle and a platform with a flap were placed inside a
rectangular tank filled with water. Pressure distribution and water
surface elevations were measured in different conditions.
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Fig. 10 &11 Recordings at the static water level set at 1 inch from the platform and
the air jet set at nominal flow rate of 150 SCFH. SFCH
Fig. 5 Schematic of velocity measurement test.
Fig. 1 Power Augmented Ram (PAR) vehicle.
0 Degree
0
— High speed (>100 knots)
— High seaworthiness
— Reasonably low thrust-to-weight ratio 0.15-0.25
— Amphibious capability (for landing operations and
transportation in Arctic regions)
Fig. 2 Detailed description of a PAR vehicle.
1/2
Air Pressure
inH2O
• PAR vehicles apply ground effect and ram air from jet engines or
fans to minimize surface drag and achieve amphibious capabilities.
• The air jet was placed at five inches above the table top with a board on
each side of the jet. A thin pitot tube was utilized with its opening
towards the mouth of the air jet to measure the airflow velocities.
Water Deformation
Velocity (m/s)
• A Power Augmented Ram (PAR) vehicle is a ground-effect craft that
travels close to a surface such as water, land, snow or ice.
• The second experiment was aimed at measuring airflow velocities and
thrust of a free air jet.
h (in)
Introduction
Acknowledgments
0
5
10
x (in)
Fig. 8 & 9 Recordings at the static water level set at 1½ inches from the platform
and the air jet set at nominal flow rate of 150 SCFH.
• The author would like to thank Dr. Matveev, Dr. Richards, Chris Chaney,
Andrew Robinson for research guidance and technical assistance.
• This work was supported by the National Science Foundation’s REU
program under grant number NSF: EEC 1157094 .