numerical simulation

With today’s supercomputing power, it’s possible to simulate entire thunderstorms to study how and why some of them can spawn deadly tornadoes. The animation above comes from a computer simulation of a supercell thunderstorm. The simulation uses initial conditions from a 2011 storm that produced an EF-5 tornado – the highest category of tornado, based on its wind speeds. To see more of the simulation, check out the video below. One thing that might surprise you is just how enormous the towering supercell clouds are compared to the tornado produced in the simulation. Often what we can see of a storm from the ground is only the tiniest part of what goes into producing it. (Image credit: L. Orf et al., source; GIF via @popsci; video credit: UWSSEC)

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SCIENTISTS TAKE FIRST TENTATIVE STEPS TO EXPLORE POTENTIAL CLIMATE OF PROXIMA B

The quest to discover whether a planet orbiting our closest neighbouring star, Proxima Centauri (4.2 light-years or 25 trillion miles from Earth), has the potential to support life has taken a new, exhilarating twist.

The planet was only discovered in August 2016, and is thought to be of similar size to Earth, creating the possibility that it could have an ‘Earth-like’ atmosphere. Scientists from the University of Exeter have embarked on their first, tentative steps to explore the potential climate of the exoplanet, known as Proxima B.

Early studies have suggested that the planet is in the habitable zone of its star Proxima Centauri – the region where, given an Earth-like atmosphere and suitable structure, it would receive the right amount of light to sustain liquid water on its surface. Now, the team of astrophysics and meteorology experts have undertaken new research to explore the potential climate of the planet, towards the longer term goal of revealing whether it has the potential to support life.

Using the state-of-the-art Met Office Unified Model, which has been successfully used to study the Earth’s climate for several decades, the team simulated the climate of Proxima B if it were to have a similar atmospheric composition to our own Earth. The team also explored a much simpler atmosphere, comprising nitrogen with traces of carbon dioxide, as well as variations of the planet’s orbit. This allowed them to both compare with, and extend beyond, previous studies.

Crucially, the results of the simulations showed that Proxima B could have the potential to be habitable, and could exist in a remarkably stable climate regime. However, much more work must be done to truly understand whether this planet can support, or indeed does support life of some form.

The research is published in leading scientific journal, Astronomy & Astrophysics, on Tuesday, May 16, 2017

Dr. Ian Boutle, lead author of the paper, explained: “Our research team looked at a number of different scenarios for the planet’s likely orbital configuration using a set of simulations. As well as examining how the climate would behave if the planet was ‘tidally-locked’ (where one day is the same length as one year), we also looked at how an orbit similar to Mercury, which rotates three times on its axis for every two orbits around the Sun (a 3:2 resonance), would affect the environment.”

Dr. James Manners, also an author on the paper added: “One of the main features that distinguishes this planet from Earth is that the light from its star is mostly in the near infrared. These frequencies of light interact much more strongly with water vapour and carbon dioxide in the atmosphere which affects the climate that emerges in our model.”

Using the Met Office software, the Unified Model, the team found that both the tidally-locked and 3:2 resonance configurations result in regions of the planet able to host liquid water. However, the 3:2 resonance example resulted in more substantial areas of the planet falling within this temperature range. Additionally, they found that the expectation of an eccentric orbit, could lead to a further increase in the “habitability” of this world.

Dr. Nathan Mayne, scientific lead on exoplanet modeling at the University of Exeter and an author on the paper added: “With the project we have at Exeter we are trying to not only understand the somewhat bewildering diversity of exoplanets being discovered, but also exploit this to hopefully improve our understanding of how our own climate has and will evolve.”

The University of Exeter has one of the UK’s largest astrophysics groups working in the fields of star formation and exoplanet research. The group focuses on some of the most fundamental problems in modern astronomy, such as when do stars and planets form and how does this happen. The group conduct observations with the world’s leading telescopes and carry out numerical simulations to study young stars, their planet-forming discs, and exoplanets. This research helps to put our Sun and the solar system into context and understand the variety of stars and planetary systems that exist in our galaxy.

Scientists take first tentative steps to explore potential climate of Proxima B

The quest to discover whether a planet orbiting our closest neighboring star, Proxima Centauri (4.2 light years or 25 trillion miles from Earth), has the potential to support life has taken a new, exhilarating twist.

The planet was only discovered in August 2016, and is thought to be of similar size to Earth, creating the possibility that it could have an `Earth-like’ atmosphere. Scientists from the University of Exeter have embarked on their first, tentative steps to explore the potential climate of the exoplanet, known as Proxima B.

Keep reading

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Music from Another Star

“We used a numerical simulation of TRAPPIST-1 to play a piano note every time a planet passes in front of the star (a ‘transit’) and a drum every time a faster inner planet overtakes its outer neighbour (a 'conjunction’). To assign pitches, we simply scaled up the orbital frequencies by 212 million times to bring them into the human hearing range. The TRAPPIST-1 system is a resonant chain which means that the periods of the planets’ orbits are very close to whole number ratios (ex. 3:2, 4:3). This is exactly what makes two musical notes sound consonant when played together and as a result, TRAPPIST-1 creates a beautiful, but slightly twisted harmony. For the same reason, the transits and conjunctions occur in a steady, repeating pattern. The crackling sound heard towards the end is Kepler’s K2 lightcurve data of the star’s observed brightness sped up by many times.”

Matt Russo, Dan Tamayo and Andrew Santaguida

HEY I NEED HELP AGAIN!

SO I am making a numerical simulation of a bouncing ball but something is wrong with the code here is what the output looks like:

68
51.5
29.225
0
hit the floor! NOW BOUNCE
20
83
GOING DOWWWWWWNNNN!!!!
71.3
55.2125
33.4944
4.35589
0
hit the floor! NOW BOUNCE
20
83
GOING DOWWWWWWNNNN!!!!
71.3
55.2125
33.4944
4.35589
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
hit the floor! NOW BOUNCE
20
GOING DOWWWWWWNNNN!!!!
2
0
——————————————————-etc

as you can see after a millisec it starts repeating. What I want it to end with is a ball that is just rolling on the ground, not a ball that infinitely bounces a certain a height then back down.

here is the code I used:

Source.cpp:

#include <iostream>

using namespace std;

double ball_d = 5.0, floor_d = 1000.0, gravity = 0, height_init = 80.0, c = 0.1, height;
double force, o = 0.1, force_init;

void bounce() {
force = floor_d / ball_d - height;
force_init = force;
height_init -= force_init * o;
while (1 == 1) {
force = floor_d / ball_d - height;
height = force * o + height;
o += 0.25;
if (height >= height_init) {
cout << height << endl;
cout << “GOING DOWWWWWWNNNN!!!!” << endl;
break;
}
else cout << height << endl;
}
o = 0.1;
}

int main() {
height = height_init;
while (1 == 1) {
gravity = floor_d / ball_d - height;
height = height - (gravity * c);
c += 0.025;
if (height <= 0) {
height = 0;
cout << height << endl;
cout << “hit the floor! NOW BOUNCE” << endl;
bounce();
c = 0.1;
}
else cout << height << endl;
}
system(“PAUSE”);
return 0;
}

Every year newts move to the water in the springtime to mate before returning to land for the rest of the year. This annual aquatic relocation is accompanied by changes in the newt’s body. Flaps of skin grow from their upper jaw to their lower jaw, partially closing their mouths at the corners. This can be seen in the left column of the animation compared to the center and right. 

Numerical simulation shows that this mouth change has a significant impact on the newt’s ability to hunt underwater. Newts are suction feeders, who open their jaws and expand their mouth cavity to suck in water and their prey. By closing off the corners of their mouths during their aquatic phase, the newts generate more suction, reaching peak flow velocities 10% to 50% higher than in their terrestrial form and enabling them to pull prey from 15% further away. When they leave the water, the newts lose the extra flaps so that their mouths can open wider for catching prey on land. (Image credit: S. Van Wassenbergh and E. Heiss, source)

shoebill-san  asked:

are blood jets realistic? when someone gets shot in the movies?

This one’s a bit tough to boil down to a yes or a no, honestly. While piercing an artery can cause jetting (more on that below), movies tend to exaggerate the effect. And even among Hollywood movies, there’s a broad variation in how wounds are represented. I’m pretty sure no one thinks that blood actually behaves like it does in Monty Python or a Tarantino film!

That said, depending on the wound, there can be a jetting effect thanks to the pulsing of our hearts. Scientists have even worked to numerically simulate human blood flow after a wound. I’ve included a video example below. Be warned - some viewers may find it gross. That said, there’s nothing all that graphic on display.

As you can see, wounds to arteries have an apparent jetting motion thanks to our pulses. Bleeding from veins tends to look more uniform because the pressure pulse caused by each heartbeat has been smoothed out by the viscous effects of all the blood vessels in between. (Video credit: K. Chong et al.)

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Numerical Simulation of Nix’s Rotation

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Though they may appear random at first glance, turbulent flows do possess structure. The video above shows a numerical simulation of a mixing layer, a flow in which two adjacent regions of fluid move with different velocities. The upper third of the frame shows a top view, and the bottom frame shows a side view, in which the upper fluid layer moves faster than the lower one. The difference in velocities creates shear which quickly drives the mixing layer into turbulence. But watch the chaos carefully, and your eye will pick out vortices rolling clockwise in the largest scales of the mixing layer. These features are known as coherent structures, and they are key to current efforts to understand and model turbulent flows. (Video credit: A. McMullan)

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Anyone who has spent much time in an urban environment is familiar with the gusty turbulence that can be generated by steady winds interacting with tall buildings. To the atmospheric boundary layer–the first few hundred meters of atmosphere just above the ground–cities, forests, and other terrain changes act like sudden patches of roughness that disturb the flow and generate turbulence. The video above shows a numerical simulation of flow over an urban environment. The incoming flow off the ocean is relatively calm due to the smoothness of the water. But the roughness of an artificial island just off the coast acts like a trip, creating a new and more turbulent boundary layer within the atmospheric boundary layer. It’s this growing internal boundary layer whose turbulence we see visualized in greens and reds. (Video credit: H. Knoop et al.)