Questions tagged [curvilinear-coordinates]
Use this tag for questions about coordinate systems for Euclidean space for which coordinate lines may be curved.
82 questions
0 votes
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60 views
Vector Laplacian in Frenet–Serret coordinates with zero torsion
I am trying to follow this paper:https://accelconf.web.cern.ch/p03/papers/WPAB088.pdf and I would like to derive the Laplacian of a divergence-free vector field where the space curve has zero torsion ...
0 votes
1 answer
50 views
Calculating coordinates out of basis vectors
In the theory of generalized (curvilinear) coordinates, usually one defines coordinates first, e.g. $(u^1,u^2,u^3)$, then a position vector $\mathbf{r}(u^1,u^2,u^3)$, and finally the basis vectors, $$ ...
0 votes
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54 views
General formula for $\nabla^2 \mathbf A$ in curvilinear coordinates
In the following, $U$ is a scalar field while $\mathbf A$ is a vector field. The symbol $\partial_r$ stands for $\partial/ \partial q_r$ where $(q_1,q_2,q_3)$ are curvilinear coordinates. Some well ...
0 votes
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45 views
Does Cartesian projection onto a Frenet frame include curvature corrections?
I’m working with Reynolds‐stress production tensor and I need to be sure whether my projection from Cartesian coordinates into a curved Frenet frame already accounts for the extra Christoffel terms (i....
0 votes
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51 views
Is this a possible definition for the Levi-Civita connection coefficients?
Let $\mathcal{M}$ be a Riemannian manifold. Let $(U,x)$ be the Riemann normal coordinates about some chart $U$. Let $(U,y)$ be some arbitrary coordinates. Define $D := x(U) \cap y(U) \subset \mathbb{R}...
1 vote
0 answers
82 views
inconsistency in upper and lower index dynamics in differential geometry
Consider relaxation of a vector field $\textbf{T}$ to the minimum of a free energy in a curvilinear coordinate with orthogonal basis and a metric $g_{ij}$. The free energy is defined as $F= \int dv f,$...
2 votes
2 answers
252 views
using christoffel symbol gives a wrong divergence in spherical coordinate
I am trying to use the following formula for spherical coordinate to find the divergence of a velocity field. The formula reads $$\nabla_k u^k = (\frac{\partial u^k}{\partial x_k}+ u^j \Gamma_{kj}^i) ....
1 vote
0 answers
114 views
Laplacian of a rank two tensor in curvilinear coordinate
Could some one post the formula (or a reference) on laplacian of a rank two tensor in curvilinear coordinate? I have spent hours looking for it with no success. in particular, I found two ...
1 vote
1 answer
91 views
Algorithm to extend function $f(x,y)$ to orthogonal curvilinear coordinate system
Given a (sufficiently nice) function $f(x,y) : \mathbb{R}^2 \to \mathbb{R}$, how would one find a function $g(x,y)$ such that $(f,g)$ form a 2-D orthogonal curvilinear basis (i.e. if the contour lines ...
0 votes
1 answer
82 views
Understanding the Equation for Unit Vectors in Curvilinear Coordinate Systems
I am trying to understand the derivation of divergence in curvilinear coordinate systems. I stumbled upon this equation and it seems enigmatic to me. I know that $\mathbf{e}_{u_i}$ are the unit ...
4 votes
0 answers
233 views
Finding Lamé coefficients (scale factors) for the curves
I am having trouble finding the Lamé coefficients for the following curves. I have specified all the necessary theory, however I am not sure how to practically compute it. $$ \begin{cases} x = \frac{...
0 votes
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76 views
Can the two curve $x=a$, $y^2 + x=b$ form a coordinate system?
I'm interested in constructing a curvilinear coordinate system with coordinate axes being these two curves: $$x=a, \qquad y^2+x=b,$$ where $a, b$ are parameters that specify the families of the curve, ...
4 votes
1 answer
181 views
Is knowing unit basis vector enough to specify a coordinate system?
In orthonormal curvilinear coordinate system, we define unit basis vector as $$\mathbf{\hat{e}}_u = \frac{1}{h_u} \frac{d\mathbf{r}}{du},$$ where $h_u = |\frac{d\mathbf{r}}{du}|$. Suppose we only know ...
0 votes
1 answer
180 views
Families of orthogonal curves to parabola.
In a typical ODE course, we learn that families of orthogonal curves to parabola $y=Ax^2$ are given by families of ellipses, given by $x^2/2+y^2=c^2$. However, there is this thing called parabolic ...
1 vote
1 answer
130 views
Curvilinear Coordinate with coordinate curves that look like cosine in 2D
There are curvilinear coordinates with coordinate curves that look like rays and circles, i.e. polar coordinates, and there are curvilinear coordinates with coordinate curves that look like parabolas, ...