Tractor-trailers are used all across America to transport cargo, but are not designed with fuel efficiency in mind. Therefor, there is an incentive for companies to invest in making their tractor-trailers more aerodynamic in order to save on fuel costs. I go into the testing and methodology of how my team and I decided to tackle the problem of reducing the coefficient of drag on tractor-trailers by implementing air channeling devices (ACDs). Then, I cover the results from our experiments and our ACD recommendation.
Tractor-trailers are used all across America to transport cargo, but are not designed with fuel efficiency in mind. Therefor, there is an incentive for companies to invest in making their tractor-trailers more aerodynamic in order to save on fuel costs. I go into the testing and methodology of how my team and I decided to tackle the problem of reducing the coefficient of drag on tractor-trailers by implementing air channeling devices (ACDs). Then, I cover the results from our experiments and our ACD recommendation.
Solution to AERMOD/PRIME PM10 Overpredictions for Extremely Short, Long and W...Sergio A. Guerra
The current formulation in AERMOD/PRIME is prone to downwash overestimations as documented by Petersen et al. Some of these overpredictions can be minimized by conducting a wind tunnel study to refine the building inputs used in AERMOD/PRIME for critical stacks and wind directions. Most of the wind tunnel studies conducted to date involve taller building structures of at least 20 meters in height. However, a recent wind tunnel study was conducted for the Basic American Foods, Blackfoot, Idaho facility, which has extremely short buildings (7 to 12 meters in height) with very long and wide footprints and many exhaust stacks which are less than 25 meters above ground
The wind tunnel study confirmed that AERMOD was vastly overstating downwash effects for certain critical wind directions. In some cases, AERMOD-predicted concentrations were almost four times higher without the wind tunnel refinements. This study indicates that the previously identified tendency of AERMOD to overpredict downwash using the traditional BPIP-derived building inputs also applies to sites with shorter buildings. Because shorter buildings with shorter stacks are common in many sources subject to the minor New Source Review program (such as most food and beverage and manufacturing facilities), AERMOD’s overpredictions may be causing significantly higher predicted concentrations for many industrial sources.
This paper describes the wind tunnel study performed for this site, presents the benefits obtained from these building input refinements, and reviews comments received on the project from regulatory agencies.
A Comparison of Panel Method and RANS Calculations for a Horizontal Axis Mari...João Baltazar
In this work, a comparison between results of a panel method and a RANS solver is made for a horizontal axis marine current turbine in uniform inflow conditions. The panel method calculations were made with panel code PROPAN (Baltazar, On the modelling of the potential flow about wings and marine propellers using a boundary element method. Ph.D. thesis, Instituto Superior Técnico, 2008). A vortex pitch wake alignment model is considered for the blade wake. The RANS calculations were carried out with RANS code ReFRESCO (http:// www. marin. nl/ web/ Facilities-Tools/ CFD/ ReFRESCO. htm). A comparison of the blade pressure distributions, wake geometry and thrust and power coefficients is made. A reasonable to good agreement of the blade distribution and turbine forces is seen between the codes. Comparison of the numerical calculations with experimental performance data available in the literature is also presented. In general, the trend of the thrust and power coefficients is well captured by the numerical methods.
Development and Implementation of a Washout Algorithm for a 6-dof Motion Plat...IJRES Journal
Flight simulators for pilot training is extremely important due safety and economic factors.
Flight simulator needs to simulate different kinds of complicated motion state such as roll, pitch and yaw
angles. It has six-degree of freedom, high precision, high rigid, modular design and many other advantages. The
motion system responds to the aircraft linear and angular accelerations in order to compute the most
appropriate cabin motion to replicate these accelerations, subject to the displacement limits and the velocity
limits of the actuators. The cabin accelerations are filtered in order to compute the most appropriate cabin
motion to replicate the actual airplane accelerations. This paper developed and implemented a motion washout
algorithm that can enhance the fidelity of motion platform and the cabin motion never exceeds the mechanical
limits of the motion platform, particularly the maximum actuator displacements and the maximum actuator
velocities.
Simulation in Action: Fatigue Analysis on 1243 Scraper Tail Adaptive Corporation
Walk through a design simulation example with a 1243 Scraper Tail. In this example, this large piece of equipment needed to fit into a shipping container. They needed to:
- Understand time history loading of their system in operation
- Create a representative duty cycle of their system
- Calculate Fatigue life of their system (welded structure)
- Identify where they can optimally minimize weight and cost of their system.
Learn how they accomplished this using Simulation software...
Solution to AERMOD/PRIME PM10 Overpredictions for Extremely Short, Long and W...Sergio A. Guerra
The current formulation in AERMOD/PRIME is prone to downwash overestimations as documented by Petersen et al. Some of these overpredictions can be minimized by conducting a wind tunnel study to refine the building inputs used in AERMOD/PRIME for critical stacks and wind directions. Most of the wind tunnel studies conducted to date involve taller building structures of at least 20 meters in height. However, a recent wind tunnel study was conducted for the Basic American Foods, Blackfoot, Idaho facility, which has extremely short buildings (7 to 12 meters in height) with very long and wide footprints and many exhaust stacks which are less than 25 meters above ground
The wind tunnel study confirmed that AERMOD was vastly overstating downwash effects for certain critical wind directions. In some cases, AERMOD-predicted concentrations were almost four times higher without the wind tunnel refinements. This study indicates that the previously identified tendency of AERMOD to overpredict downwash using the traditional BPIP-derived building inputs also applies to sites with shorter buildings. Because shorter buildings with shorter stacks are common in many sources subject to the minor New Source Review program (such as most food and beverage and manufacturing facilities), AERMOD’s overpredictions may be causing significantly higher predicted concentrations for many industrial sources.
This paper describes the wind tunnel study performed for this site, presents the benefits obtained from these building input refinements, and reviews comments received on the project from regulatory agencies.
A Comparison of Panel Method and RANS Calculations for a Horizontal Axis Mari...João Baltazar
In this work, a comparison between results of a panel method and a RANS solver is made for a horizontal axis marine current turbine in uniform inflow conditions. The panel method calculations were made with panel code PROPAN (Baltazar, On the modelling of the potential flow about wings and marine propellers using a boundary element method. Ph.D. thesis, Instituto Superior Técnico, 2008). A vortex pitch wake alignment model is considered for the blade wake. The RANS calculations were carried out with RANS code ReFRESCO (http:// www. marin. nl/ web/ Facilities-Tools/ CFD/ ReFRESCO. htm). A comparison of the blade pressure distributions, wake geometry and thrust and power coefficients is made. A reasonable to good agreement of the blade distribution and turbine forces is seen between the codes. Comparison of the numerical calculations with experimental performance data available in the literature is also presented. In general, the trend of the thrust and power coefficients is well captured by the numerical methods.
Development and Implementation of a Washout Algorithm for a 6-dof Motion Plat...IJRES Journal
Flight simulators for pilot training is extremely important due safety and economic factors.
Flight simulator needs to simulate different kinds of complicated motion state such as roll, pitch and yaw
angles. It has six-degree of freedom, high precision, high rigid, modular design and many other advantages. The
motion system responds to the aircraft linear and angular accelerations in order to compute the most
appropriate cabin motion to replicate these accelerations, subject to the displacement limits and the velocity
limits of the actuators. The cabin accelerations are filtered in order to compute the most appropriate cabin
motion to replicate the actual airplane accelerations. This paper developed and implemented a motion washout
algorithm that can enhance the fidelity of motion platform and the cabin motion never exceeds the mechanical
limits of the motion platform, particularly the maximum actuator displacements and the maximum actuator
velocities.
Simulation in Action: Fatigue Analysis on 1243 Scraper Tail Adaptive Corporation
Walk through a design simulation example with a 1243 Scraper Tail. In this example, this large piece of equipment needed to fit into a shipping container. They needed to:
- Understand time history loading of their system in operation
- Create a representative duty cycle of their system
- Calculate Fatigue life of their system (welded structure)
- Identify where they can optimally minimize weight and cost of their system.
Learn how they accomplished this using Simulation software...
On March 24, ICLR conducted a Friday Forum workshop entitled ‘Practical issues in updating IDF curves for future climate: ‘Physics’ vs climate models’, with Dr. Slobodan Simonovic of Western University. A tool for updating IDF curves for future climate (developed at Western and hosted by ICLR) has been in the public domain since March of 2015. It has over 700 registered users and averages 7,000 sessions per year. The direct use of global climate models (GCMs) and statistical downscaling procedures results in a range of values for updating IDF curves that immediately raises the question which one should be used in practice. At the same time, various discussions have been pointing to a ‘more robust’ alternative approach of using direct scaling of temperature - an approach based on ‘physics’ (Clausius-Clapeyron relationship). The main objectives of this presentation are (i) to provide comparative analysis of the IDF updating tool and ‘physics’ based approach of direct temperature scaling for Canada; and (ii) to provide more practical (engineering-based) guidance on how to use updated IDF relationships.
Slobodan P. Simonovic is globally recognized for his unique interdisciplinary research in Systems Analysis and the development of deterministic and stochastic simulations, optimization, multi criteria analysis, and other decision-making methodologies for addressing challenging system of systems problems lying at the confluence of society, technology and the environment, with applications in water resources management, hydrology, energy, climate change and public infrastructure, from a sustainable development perspective. His main contributions include modelling risk and resilience of complex systems.
Highlights from the 2016 Guideline on Air Quality Models ConferenceSergio A. Guerra
The revision of the Guideline on AQ Models (Appendix W) will prompt many changes in the way dispersion modeling is conducted for regulatory purposes. Some of the changes to the Guideline include enhancements and bug fixes to the AERMOD modeling system, new screening techniques to address ozone and secondary PM2.5, delisting CALPUFF as the preferred long-range transport model, and updates on the use of meteorological input data. These changes will have a significant impact on the regulated community. In anticipation of these updates, the Air & Waste Management Association will hold its 6th Specialty Conference: “Guideline on Air Quality Models: The New Path” to provide a technical forum to discuss the Guideline. This talk covered the main highlights from this conference including the presentations from EPA on the status and future direction of the Guideline. Learn how these changes may impact dispersion modeling evaluations for short and long range transport.
Model predictive-based shunt active power filter with a new reference current...Asoka Technologies
This study presents a new reference current estimation method using proposed robust extended complex Kalman filter (RECKF) together with model predictive current (MPC) control strategy in the development of a three-phase shunt active power filter (SAPF). A new exponential function embedded into the RECKF algorithm helps in the estimation of in phase fundamental component of voltage (vh) at the point of common coupling considering grid perturbations such as distorted voltage, measurement noise and phase angle jump and also for the estimation of fundamental amplitude of the load current (ih). The estimation of these two variables (vh, ih) is used to generate reference signals for MPC. The proposed RECKF-MPC needs less number of voltage sensors and resolves the difficulty of gain tuning of proportional–integral (PI) controller. The proposed RECKF-MPC approach is implemented using MATLAB/SIMULINK and also Opal-RT was used to obtain the real-time results. The results obtained using the proposed RECKF together with different variants of Kalman filters (Kalman filter (KF), extended KF (EKF) and extended complex KF (ECKF)) and PI controller are analysed both in the steady state as well as transient state conditions. From the above experimentation, it was observed that the proposed RECKF-MPC control strategy outperforms over PI controller and other variants of Kalman filtering approaches in terms of reference tracking error, power factor distortion and percentage total harmonic distortion in the SAPF system.
A renewed interest and scrutiny of downwash shortcomings has fueled a parallel, yet complementary effort, led by industry and EPA. Industrial groups funded the update to the Plume Rise Model Enhancements (PRIME) formulation in AERMOD based on new equations derived from wind tunnel measurements. Concurrently, EPA’s Office of Research and Development (ORD) conducted research that led to new enhancements to the downwash formulation.2 The new PRIME equations (PRIME2), along with EPA-ORD’s building downwash improvements, have been included as alpha options in an upcoming new EPA version of AERMOD.
As part of the renewed interest in building downwash, the PRIME2 subcommittee under the A&WMA APM committee was formed to: (1) establish a mechanism to review, approve and implement new science into the model for this and future improvements; and (2) provide a technical review forum to improve the PRIME building downwash algorithms. Collaboration and cooperation from EPA’s ORD and OAQPS have been on-going during this research project. These efforts included a downwash summit at EPA’s RTP facilities on February 16, 2018 where representatives of the PRIME2 committee and research funders met with EPA’s ORD and OAQPS staff to discuss the newly developed building downwash improvements. During that meeting it was decided that these enhancements would be included as new alpha options in AERMOD. The intent is that these experimental options will be tested by the user community to create enough justification to transition them to a beta status (approved on a case-by-case basis) and eventually to default options in AERMOD. An evaluation of some of these new downwash options is presented.
The Plume Rise Model Enhancements (PRIME) formulation in AERMOD has been updated based new equations developed from wind tunnel measurements taken downwind of various solid and streamlined structures. These new equations, along with other building downwash improvements have been included as alpha options in the upcoming new version of AERMOD. The PRIME2 options include: • PRIME2UTurb which enables enhanced calculations of turbulence and wind speed • PRIME2Ueff which defines the height used to compute effective parameters Ueff, Sweff, Sveff and Tgeff at plume height and at 30 m • Streamline defines the set of constants for modeling all structures as streamlined. If omitted, rectangular building constants are used. The ORD Options include: • PRIMEUeff which controls the heights for which the wind speed is calculated for the main plume concentrations. • Average between plume height and receptor height recommended in ORD version • Default is current method in AERMOD, stack height wind speed. • PRIMETurb which adjusts the vertical turbulence intensity, wiz0 from 0.6 to 0.7. • PRIMECav modifies the cavity calculations These improvements aim to address important theoretical issues that significantly affect the accuracy of predicted concentrations subject to downwash effects. This research effort was funded in part by the American Petroleum Institute, the Electric Power Research Institute, the Corn Refiners Association and the American Forest & Paper Association. As part of it, the PRIME2 subcommittee under the A&WMA APM committee was formed to: (1) establish a mechanism to review, approve and implement new science into the model for this and future improvements; and (2) provide a technical review forum to improve the PRIME building downwash algorithms. Collaboration and cooperation from the EPA Office of Research and Development (ORD) has been on-going during the research project resulting in new alpha options aimed at solving known issues with the treatment of building downwash effects in AERMOD. The intent is that these experimental options will be tested by the user community to create enough justification to make these beta (approved on a case-by-case basis) and eventually default options in AERMOD. A preliminary evaluation for the following four cases will be presented: • Arconic- Davenport, IA (formerly Alcoa) • Mirant Potomac River Generating Station- Alexandria, VA • Basic American Foods- Blackfoot, ID • Oakley Generating Station- Oakley, CA The evaluation includes comparing 1-hr, 24-hr and annual averages along with Q-Q plots and isopleths. A discussion related to the results obtained will also be presented.
Dimensioning of a Furling System for a Small Wind TurbineFlorian Roscheck
This presentation describes how to design a furling system for a small wind turbine. It reviews three different approaches to furling system design from literature and then presents the design approach that was used for designing the furling system of the HOLI 300 small wind turbine.
This presentation created and addressed by Jesús Fernandez (University of Cantabria) in the intensive three day course from the BC3, Basque Centre for Climate Change and UPV/EHU (University of the Basque Country) on Climate Change in the Uda Ikastaroak Framework.
The objective of the BC3 Summer School is to offer an updated and multidisciplinary view of the ongoing trends in climate change research. The BC3 Summer School is organized in collaboration with the University of the Basque Country and is a high quality and excellent summer course gathering leading experts in the field and students from top universities and research centres worldwide.
Open-Water Thrust and Torque Predictions of a Ducted Propeller System With a ...João Baltazar
This paper discusses several modelling aspects which are important for the performance predictions of a ducted propulsor with a low-order Panel Method. The aspects discussed are the alignment of the wake geometry, the influence of the duct boundary layer on the wake pitch and the influence of a transpiration velocity through the gap. The analysis is carried out for propeller Ka4-70 operating without and inside a modified duct 19A, in which the rounded trailing edge is replaced by a sharp trailing edge. Experimental data for the thrust and torque are used to validate the numerical results. The pitch of the tip vortex is found to have a strong influence on the propeller and duct loads. A good agreement with the measurements is achieved when the wake alignment is corrected for the presence of the duct boundary layer.
Performance Enhancement of Shunt Active Power filter using a Kalman Filter ba...Asoka Technologies
This paper proposes a Kalman filter (KF) based H∞ control scheme for a three phase shunt active power filter (SAPF) system. For the current control loop, a H∞ controller is designed with a mixed sensitivity approach for achieving stability and high disturbance rejection in the SAPF system. A new current reference scheme is also proposed that employs KF to avoid synchronization circuit and proportional integral (PI) controller loop resulting in a reliable and cost-effective SAPF system. This reference scheme can self-regulate the dc-link voltage by a fast and adaptive estimation of the source reference current with power system perturbations raised in source or load sides. The efficacy of the proposed KF-H∞ control algorithm is evaluated through comparison with an existing PI and PI plus vector PI (PI-PIVPI) algorithm and then validated with experimental studies pursued using a dSPACE1104. From the obtained experimental results, it is observed that the proposed SAPF significantly outperforms the existing PI-PIVPI in terms of exhibiting robustness to modeling uncertainties and insensitivity to grid perturbations such as harmonics, measurement noise and phase angle jump. Thus, the power quality improvement is achieved in terms of perfect current harmonics cancellation as well as power factor improvement.
Optimization of Closure Law of Guide Vanes for an Operational Hydropower Plan...Dr. Amarjeet Singh
This paper addresses the optimization of twostage closure law of guide vanes in an operational
hydropower plant of Nepal. The mathematical model
has been established in commercial software Bentley
Hammer, whose correctness has been validated by
comparing the results with the data of experimental
load rejection test. The validated mathematical model
has been employed to find the parameters of optimum
closure pattern, which minimizes the non-linear
objective function of maximum water pressure and
maximum rotational speed of turbine.
Optimization of Closure Law of Guide Vanes for an Operational Hydropower Plan...
PPT
1. August, 2016
AMOL NARENDRA PAWAR
Dynamic positioning of hydrofoil using
RANS computations
Thesis submitted to École Centrale de Nantes in fulfillment of the requirement
for the Degree of Master of Science in Computational Mechanics
Supervisor: Dr. Jeroen WACKERS, LHEEA, C.N.R.S.
3. Contents
Introduction
Algorithm for 3d hydrofoil
Principle of adapted algorithm
Case study
Tests performed on the algorithm
Parameter Extractions
Mathematical model
Least square fitting
Tests on extracted parameters
Conclusion and future scope
14/09/2016Dynamic positioning of hydrofoil3
4. Introduction
Objective
14/09/2016Dynamic positioning of hydrofoil4
Current situation: dynamic positioning algorithm for hydrofoils (2d)
Target : To have an algorithm to search for a stable elevation height of the
hydrofoil for a given imposed vertical force.
5. Algorithm for 3d hydrofoil
Principle of adapted algorithm
14/09/2016Dynamic positioning of hydrofoil5
Vertical Velocity
Imposed Force
Variable imposed
force
Target lifting
force
Corrected Actual
Lift Force
Added mass
correction in X
direction
Added mass
Correction in Z
direction
Vertical Velocity
Influence
Correction
i
z
v
i
z
e
zIMP
z F
D
FF
F
LAMAMFF xaxzazz
COR
z
2
v
e
z
IMP
z
COR
z
z
DF
FF
CV
6. Algorithm for 3d hydrofoil
Principle of adapted algorithm- Corrected lift force
14/09/2016Dynamic positioning of hydrofoil6
Added mass correction in z direction
Added mass correction in x direction
Vertical velocity influence correction
Az
Fz
az
D
D
M
Ax
Fx
ax
D
D
M
LCSVL 2
2
1
7. Algorithm for 3d hydrofoil
Case study- AC72 hydrofoil
14/09/2016Dynamic positioning of hydrofoil7
Hydrofoil
elevation(m)
Generated Lift
force(N)
0.5 -4456
0 22465
-0.5 58374
-1 69685
-2 80531
Span (b) 2.5 m
Chord (c) 1 m
Speed (V) 20 m/s
Angle of attack ( ) 1 deg.
8. Tests performed on the algorithm
Test 1: Analysis of the effect of added mass correction in x direction
14/09/2016Dynamic positioning of hydrofoil8
Induced noise x acceleration No effect of noise on the lifting force
9. Tests performed on the algorithm
Test 2: Analysis of the vertical velocity influence correction
14/09/2016Dynamic positioning of hydrofoil9
Case1: Lifting force coefficient approximation using infinite wing theory
Case 2: Lifting force coefficient approximation using finite wing theory
Where:
2LC
AR
a
a
CL
0
0
1
20a
S
b
AR
2
bcS
2
1
10. Tests performed on the algorithm
Test 2 Analysis of the vertical velocity influence correction
14/09/2016Dynamic positioning of hydrofoil10
Infinite wing theory approximation Finite wing theory approximation
Partially immersed hydrofoil position h=0
11. Tests performed on the algorithm
Test 2 Analysis of the vertical velocity influence correction
14/09/2016Dynamic positioning of hydrofoil11
Infinite wing theory approximation Finite wing theory approximation
Completely immersed hydrofoil position h=-1m
12. Tests performed on the algorithm
Reference computations for parameter extraction
14/09/2016Dynamic positioning of hydrofoil12
8339.214
)(*10*2 IMP
zFC
Power law fit
Geometry dependent !!!
Optimal values of C constant
13. Parameter Extraction
Mathematical model
14/09/2016Dynamic positioning of hydrofoil13
Aim: To build a model to predict the vertical position of hydrofoil to converge
to an imposed force.
Saved values:
Real function:
To make it easy to integrate in developed dynamic library
),,,(
..
zzxFz
),,(
..
zzxfFz
..
4
2
.
32
2
.
1 )()( zxazxazaxaFz
..
4
2
.
3
2
.
1 )()( zxazxaxaFAMFF i
zzazz
P
z
14. Parameter Extraction
Least square fitting
14/09/2016Dynamic positioning of hydrofoil14
bAx
bAAxA TT
Over determined System
Number of unknowns = Number of equations
15. Parameter Extraction
Test 1: Imposing parametric solution just once after 300 time steps
14/09/2016Dynamic positioning of hydrofoil15
Test settings:
Forces are saved after every 5 time steps
Parameters extracted at 300th time step: from 60 saved forces
Initial guess for C constant : Power law
C after 300th time step :
3
170
a
C
16. Parameter Extraction
Test 1: Imposing parametric solution just once after 300time steps
14/09/2016Dynamic positioning of hydrofoil16
Hydrofoil elevation : -1m Hydrofoil elevation : -2m
Parametric solution is imposed very late !
Still geometry dependent – power law !
17. Parameter Extraction
Test 2: Imposing parametric solution after every 100 time step
14/09/2016Dynamic positioning of hydrofoil17
Test settings:
Forces are saved after every 5 time steps
Parameters extracted after every 100th time step: from last 20 saved
forces
Initial guess for C constant : 1
Geometry dependence of algorithm is removed
C after every 100th time step :
where, P= 60, for the case of h =-1m
and P= 30, for the case of h =-2m
3a
P
C
18. Parameter Extraction
Test 2: Imposing parametric solution after every time 100 time step
14/09/2016Dynamic positioning of hydrofoil18
Hydrofoil elevation : -1m Hydrofoil elevation : -2m
Parametric solution Vs Reference solution is not matching !
Failed to compute parameters consistently !
19. Parameter Extraction
Test 3: Verification of model with continues saving of forces
14/09/2016Dynamic positioning of hydrofoil19
Number of
saved forces
Hydrofoil elevation height
-0.5 -1 -2
25
50
Predicted elevation height converges faster than simulation height !
In early phase of computations, model over predicts the height !
20. Parameter Extraction
Test 3: Validation of model with continues saving of forces
14/09/2016Dynamic positioning of hydrofoil20
Number of
saved forces
Hydrofoil elevation height
-0.5 -1 -2
100
200
21. Conclusion and Future work
14/09/2016Dynamic positioning of hydrofoil21
Conclusion
With developed algorithm – dynamic positioning of hydrofoil is possible
With derived mathematical model – convergence rate of predicted elevation of
hydrofoil is faster
Future work
Position control procedure
Integration of mathematical model into the algorithm
