1) The document discusses compressible flow and summarizes key concepts like Mach number, speed of sound, stagnation properties, and normal shock waves.
2) It provides equations to calculate flow properties like velocity, pressure, and temperature across area changes and normal shocks.
3) Examples are given to demonstrate calculating stagnation properties, flow variables upstream and downstream of normal shocks, and solving problems involving compressible flow concepts.
Calibrating a CFD canopy model with the EC1 vertical profiles of mean wind sp...Stephane Meteodyn
For some projects, applying the basic rules of EC1 is not sufficient, and it is required to get a more accurate estimation of the wind speed on the construction site. This can be done by using computational fluid dynamics codes which have the advantage, both to take into account of the terrain inhomogeneity and to calculate 3D orographic effects. In this way, the orography and roughness effects are coupled as they are in the real world. However, applying CFD computations must be in coherence with EC1 code. Then it is necessary to calibrate the ground friction for low roughness terrains as well as the drag force and turbulence production in case of high roughness lengths due to the presence of a canopy (forests or built areas). That is the condition for such methods to be commonly used and agreed by Building Control Officers. In this mind, TopoWind has been developed especially for wind design applications and can be a very useful, practical and objective tool for wind design engineers. The canopy model implemented in TopoWind has been calibrated in order to get the mean wind and turbulence profiles as defined in the EC1 for standard terrains. In this way, TopoWind computations satisfy the continuity between the EC1 values for homogeneous terrains and the more complex cases involving inhomogeneous roughness or orographic effects
Calibrating a CFD canopy model with the EC1 vertical profiles of mean wind sp...Stephane Meteodyn
For some projects, applying the basic rules of EC1 is not sufficient, and it is required to get a more accurate estimation of the wind speed on the construction site. This can be done by using computational fluid dynamics codes which have the advantage, both to take into account of the terrain inhomogeneity and to calculate 3D orographic effects. In this way, the orography and roughness effects are coupled as they are in the real world. However, applying CFD computations must be in coherence with EC1 code. Then it is necessary to calibrate the ground friction for low roughness terrains as well as the drag force and turbulence production in case of high roughness lengths due to the presence of a canopy (forests or built areas). That is the condition for such methods to be commonly used and agreed by Building Control Officers. In this mind, TopoWind has been developed especially for wind design applications and can be a very useful, practical and objective tool for wind design engineers. The canopy model implemented in TopoWind has been calibrated in order to get the mean wind and turbulence profiles as defined in the EC1 for standard terrains. In this way, TopoWind computations satisfy the continuity between the EC1 values for homogeneous terrains and the more complex cases involving inhomogeneous roughness or orographic effects
Aerodynamics Part I of 3 describes aerodynamics of wings and bodies in subsonic flight.
For comments please contact me at solo.hermelin@gmail.com.
For more presentations on different subjects visit my website at http://www.solohermelin.com.
This presentation had been prepared for the aircraft propulsion class to my undergraduate and graduate students at Kasetsart University and Chulalongkorn University - Bangkok, Thailand.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Aerodynamics Part I of 3 describes aerodynamics of wings and bodies in subsonic flight.
For comments please contact me at solo.hermelin@gmail.com.
For more presentations on different subjects visit my website at http://www.solohermelin.com.
This presentation had been prepared for the aircraft propulsion class to my undergraduate and graduate students at Kasetsart University and Chulalongkorn University - Bangkok, Thailand.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
4. Special phenomenon associated with Comp Fluid Flow
1
(sin )
Mach Angle
M
α
When body is stationery
In case of Supersonic (M>1)
Zone of action
Zone of silence
5. Determine the velocity of a bullet fired in the air if the Mach angle is observed to
be 300 . Given that the temperature of the air is 22 0C, density 1.2 kg/m3, ϒ = 1.4
R = 287.4 J/kg K.
Ans: C = 344.6 m/s, U = 2481 km/hr
An observer on the ground hears the sonic boom of a plane 15 km above when
The plane has gone 20 km ahead of him. Estimate the speed of flight of the plane
Ans: M = 1.67
Calculate the velocity and Mach No of a supersonic aircraft flying at an altitude of
1000 m where the temperature is 280 0K. Sound of the aircraft is heard 2.15 sec
After the passage of aircraft an the head of on observer. Take ϒ = 1.4, R = 287.4 J/
Ans: V= 488.68 m/sec, M = 1.45
15 KM
20 KM
6. Effect of Area variation on flow properties in Isentropic Flow
By continuity equation tan
AV cons t
Take natural log of both side
ln ln ln ln
A V C
On Differentiation
0
d dA dV
A V
So dA d dV
A V
By Euler Equation: 0
dp
VdV
(A)
7. 2
dV dp
V V
Or
By equation (A)
2
dA d dp
A V
2
2
1
dA dp d
V
A V dp
Or
2
2 2
1
dA dp V
A V C
2
2
1
dA dp
M
A V
2
1
dA dV
M
A V
So Since
dp
c
d
V
M
C
Since
2
dV dp
V V
Since
Effect of Area variation on flow properties in Isentropic Flow con
8. Effect of Area variation on flow properties in Isentropic Flow cont..
9. Stagnation and Sonic Properties
2
0
1
2
h h V
Stagnation enthalpy (ho) is given by
We knew that h = CpT
So
Hence,
2
0
1
2
p p
C T C T V
2
2
0 1 1
1 1
2 2
p
T V
V
T TC RT
Or 2
0 1
1
2
T
M
T
Since Cp = ϒR/(ϒ-1)
Similarly 1 1
2
0 0 1
1
2
p T
M
p T
1 1
1 1
2
0 0 1
1
2
T
M
T
h
T
p
ρ
h0
T0
p0
ρ0
10. Stagnation and Sonic Properties cont
There is another set of condition where the flow is sonic i.e. M=1
These Sonic or Critical properties are denoted by asterisks: p*, T* e
2
0
1
2
p p
C T C T V
We know that
1/2
0
2
1
R
V T T
or
Max velocity is given by
1/2
max 0
2
1
R
V T
At M = 1, we can write the previous equations as
0 1
2
T
T
1
0 1
2
p
p
1
1
0 1
2
11. An aeroplane is flying at 1000 km/hr through still air having a pressure of 78.5 kN
(abs) and temperature -8 0C. Calculate on the stagnation point on the nose of the
Plane: Stagnation Pressure, Stag. Temperature and Stag. density. . Take for air =
R = 287 J/kg K and ϒ = 1.4.
Ans: p0 = 126.1 kN/m2, T0 = 30.4 0C, ρ0 = 1.448 kg/m3
Air has a velocity of 1000 km/hr at a pressure of 9.81 kN/m2 vacuum and a temp o
47 oC. Compute its stagnation properties and the local Mach No. Take atm air =
98.1 kN/m2, R = 287 J/kg K and ϒ = 1.4.
Ans: p0 = 131.3 kN/m2, T0 = 85.4 0C, ρ0 = 1.276 kg/m3
12. Normal Shock
•For supersonic flow in a passage or around a body, the downstream pressure and
Geometrical conditions may require an abrupt reduction of velocity and conseque
changes of the flow properties.
•A shock is then said to be occurred.
•Shock waves are highly localized irreversibility's In the flow. Shock formation is
possible for confined as well as for external flows.
•Normal shocks are substantially perpendicular to the flow and oblique shocks are
inclined at other angles.
13.
14. Flow Properties Across a Normal Shock
1 2
A1
P1
T1
M1
A2
P2
T2
M2
Normal
Shock
2
1
2
2
1 2
1
1
M
p
p M
2
1
2
2
1 2
1 1 2
1 1 2
M
T
T M
Mach No of a normal shock wave is always greater than
Unity in the upstream and less than Unity in the downstream.
2
1
2
2 2
1
1 2
2 1
M
M
M
Shock strength is defined by:
2
2 1
1
1
2
1
1
p p
Shock Strength M
p
2
1
2
2
1 1
1
1 2
M
M
Rankine – Hugoniot Equation
15. Calculate the downstream Mach No, pressure, temperature and shock strength o
Normal shock wave observed to occur in an air nozzle at
M1 = 2, p1 = 20 kN/m2, T1 = 300 K
Ans: p2 = 90 kN/m2, M2 = 0.575, T2 = 510 K, Shock strength = 3.5
For a normal shock wave in air, Mach No is 2. If the atmospheric pressure and air
Density are 26.5 kN/m2 and 0.413 kg/m3 respectively, determine the flow conditi
Before and after the shock wave. Take ϒ = 1.4.
Ans: M2 = 0.577, p2 = 119.25 kN/m2, ρ2 = 1.101 kg/m3, T1 = -49.4 0C
T2 = 104.3 0C, V1 = 599.4 m/s, V2 = 224.6 m/s
16. Conclusion from 1D analysis of a Normal Shock:
• A normal shock can occur only if M1 >1
• M2 must be less than 1 for a normal shock
• Entropy rise across a shock increases
• p2/p1 and T2/T1 increases with M1