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Encyclopedia > Vector fields in cylindrical and spherical coordinates

Contents


Vector fields in cylindrical coordinates

Vectors are defined in cylindrical coordinates by (ρ,φ,z), where This article describes some of the common coordinate systems that appear in elementary mathematics. ...

  • ρ is the length of the vector projected onto the X-Y-plane,
  • φ is the angle of the projected vector with the positive X-axis (0 ≤ φ < 2π),
  • z is the regular z-coordinate.

(ρ,φ,z) is given in cartesian coordinates by: Cartesian means relating to the French mathematician and philosopher Descartes, who, among other things, worked to merge algebra and Euclidean geometry. ...

left[begin{matrix} rho & = & sqrt{x^2 + y^2}  phi & = & operatorname{arctan}(y / x), & 0 le phi < 2pi  z & = & z end{matrix}right.

or inversely by:

left[begin{matrix} x & = & rhocosphi  y & = & rhosinphi  z & = & z end{matrix}right.

Any vector field can be written in terms of the unit vectors as: Vector field given by vectors of the form (-y, x) In mathematics a vector field is a construction in vector calculus which associates a vector to every point in a Euclidean space. ...

mathbf A = A_x mathbf{hat x} + A_y mathbf{hat y} + A_z mathbf{hat z} = A_rho boldsymbol{hat rho} + A_phi boldsymbol{hat phi} + A_z boldsymbol{hat z}

The cylindrical unit vectors are related to the cartesian unit vectors by:

begin{bmatrix}boldsymbol{hatrho}  boldsymbol{hatphi}  boldsymbol{hat z}end{bmatrix} = begin{bmatrix} cosphi & sinphi & 0  -sinphi & cosphi & 0  0 & 0 & 1 end{bmatrix} begin{bmatrix} mathbf{hat x}  mathbf{hat y}  mathbf{hat z} end{bmatrix}

In linear algebra, an orthogonal matrix is a square matrix G whose transpose is its inverse, i. ... In mathematics, and in particular linear algebra, the transpose of a matrix is another matrix, produced by turning rows into columns and vice versa. ...

Time derivative of a vector field in cylindrical coordinates

To find out how the vector field A changes in time we calculate the time derivatives. In cartesian coordinates this is simply:

mathbf{dot A} = dot A_x mathbf{hat x} + dot A_y mathbf{hat y} + dot A_z mathbf{hat z}

However, in cylindrical coordinates this becomes:

mathbf{dot A} = dot A_rho boldsymbol{hatrho} + A_rho boldsymbol{dot{hatrho}} + dot A_phi boldsymbol{hatphi} + A_phi boldsymbol{dot{hatphi}} + dot A_z boldsymbol{hat z} + A_z boldsymbol{dot{hat z}}

We need the time derivatives of the unit vectors. They are given by:

left[begin{matrix} boldsymbol{dot{hatrho}} & = & dotphi boldsymbol{hatphi}  boldsymbol{dot{hatphi}} & = & - dotphi boldsymbol{hatrho}  boldsymbol{dot{hat z}} & = & 0 end{matrix}right.

So the time derivative simplifies to:

mathbf{dot A} = boldsymbol{hatrho} (dot A_rho - A_phi dotphi) + boldsymbol{hatphi} (dot A_phi + A_rho dotphi) + boldsymbol{hat z} dot A_z

Gradient, divergence, curl, and laplacian in cylindrical coordinates

The specification of gradient, divergence, curl, and laplacian in cylindrical coordinates can be found in the article Nabla in cylindrical and spherical coordinates. In the above two images, the scalar field is in black and white, black representing higher values, and its corresponding gradient is represented by blue arrows. ... In vector calculus, the divergence is an operator that measures a vector fields tendency to originate from or converge upon a given point. ... This article is about the cURL command line tool. ... In vector calculus, the Laplace operator or Laplacian is a differential operator equal to the sum of all the unmixed second partial derivatives of a dependent variable. ... This is a list of some vector calculus formulae of general use in working with standard coordinate systems. ...


Vector fields in spherical coordinates

Vectors are defined in spherical coordinates by (r,θ,φ), where This article describes some of the common coordinate systems that appear in elementary mathematics. ...

  • r is the length of the vector,
  • θ is the angle with the positive Z-axis (0 <= θ <= π),
  • φ is the angle with the X-Z-plane (0 <= φ < 2π).

(r,θ,φ) is given in cartesian coordinates by: Cartesian means relating to the French mathematician and philosopher Descartes, who, among other things, worked to merge algebra and Euclidean geometry. ...

left[begin{matrix} r & = & sqrt{x^2 + y^2 + z^2}  theta & = & arccosleft( z / rright), & 0 le theta le pi  phi & = & operatorname{arctan}(y / x), & 0 le phi < 2pi end{matrix}right.

or inversely by:

left[begin{matrix} x & = & rsinthetacosphi  y & = & rsinthetasinphi  z & = & rcostheta end{matrix}right.

Any vector field can be written in terms of the unit vectors as:

mathbf A = A_xmathbf{hat x} + A_ymathbf{hat y} + A_zmathbf{hat z} = A_rboldsymbol{hat r} + A_thetaboldsymbol{hat theta} + A_phiboldsymbol{hat phi}

The spherical unit vectors are related to the cartesian unit vectors by:

begin{bmatrix}boldsymbol{hat r}  boldsymbol{hattheta}  boldsymbol{hatphi} end{bmatrix} = begin{bmatrix} sinthetacosphi & sinthetasinphi & costheta  costhetacosphi & costhetasinphi & -sintheta  -sinphi & cosphi & 0 end{bmatrix} begin{bmatrix} mathbf{hat x}  mathbf{hat y}  mathbf{hat z} end{bmatrix}

In linear algebra, an orthogonal matrix is a square matrix G whose transpose is its inverse, i. ... In mathematics, and in particular linear algebra, the transpose of a matrix is another matrix, produced by turning rows into columns and vice versa. ...

Time derivative of a vector field in spherical coordinates

To find out how the vector field A changes in time we calculate the time derivatives. In cartesian coordinates this is simply:

mathbf{dot A} = dot A_x mathbf{hat x} + dot A_y mathbf{hat y} + dot A_z mathbf{hat z}

However, in spherical coordinates this becomes:

mathbf{dot A} = dot A_r boldsymbol{hat r} + A_r boldsymbol{dot{hat r}} + dot A_theta boldsymbol{hattheta} + A_theta boldsymbol{dot{hattheta}} + dot A_phi boldsymbol{hatphi} + A_phi boldsymbol{dot{hatphi}}

We need the time derivatives of the unit vectors. They are given by:

begin{bmatrix}boldsymbol{dot{hat r}}  boldsymbol{dot{hattheta}}  boldsymbol{dot{hatphi}} end{bmatrix} = begin{bmatrix} 0 & dottheta & dotphi sintheta  -dottheta & 0 & dotphi costheta  -dotphi sintheta & -dotphi costheta & 0 end{bmatrix} begin{bmatrix} boldsymbol{hat r}  boldsymbol{hattheta}  boldsymbol{hatphi} end{bmatrix}

So the time derivative becomes:

mathbf{dot A} = boldsymbol{hat r} (dot A_r - A_theta dottheta - A_phi dotphi sintheta) + boldsymbol{hattheta} (dot A_theta + A_r dottheta - A_phi dotphi costheta) + boldsymbol{hatphi} (dot A_phi + A_r dotphi sintheta + A_phi dotphi costheta)

Gradient, divergence, curl, and laplacian in spherical coordinates

The specification of gradient, divergence, curl, and laplacian in spherical coordinates can be found in the article Nabla in cylindrical and spherical coordinates. In the above two images, the scalar field is in black and white, black representing higher values, and its corresponding gradient is represented by blue arrows. ... In vector calculus, the divergence is an operator that measures a vector fields tendency to originate from or converge upon a given point. ... This article is about the cURL command line tool. ... In vector calculus, the Laplace operator or Laplacian is a differential operator equal to the sum of all the unmixed second partial derivatives of a dependent variable. ... This is a list of some vector calculus formulae of general use in working with standard coordinate systems. ...


  Results from FactBites:
 
Vector fields in cylindrical and spherical coordinates - Definition, explanation (361 words)
3 Gradient, divergence, curl, and laplacian in cylindrical coordinates
Gradient, divergence, curl, and laplacian in cylindrical coordinates
Gradient, divergence, curl, and laplacian in spherical coordinates
NationMaster - Encyclopedia: Spherical coordinate system (1781 words)
In mathematics, the spherical coordinate system is a coordinate system for representing geometric figures in three dimensions using three coordinates: the radial distance of a point from a fixed origin, the zenith angle from the positive z-axis, and the azimuth angle from the positive x-axis.
The geographic coordinate system is an alternate version of the spherical coordinate system, used primarily in geography though also in mathematics and physics applications.
Spherical coordinates are the natural coordinates for describing and analyzing physical situations where there is spherical symmetry, such as the potential energy field surrounding a sphere (or point) with mass or charge.
  More results at FactBites »


 

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