Struct FinOutline 

pub struct FinOutline { /* private fields */ }

A fin’s outline in its own plane, for supersonic linear theory: a simple polygon of [x, y] vertices, m, with x aft of the root leading edge and y out from the root, closed along the root.

Serialize-only: an outline is built from a planform by FinOutline::from_planform, which checks it.

Implementations

impl FinOutline

pub fn points_m(&self) -> &[[f64; 2]]

The vertices, m, from the root leading edge [0, 0] around to the root trailing edge.

pub fn tip_leading_edge_m(&self) -> [f64; 2]

The tip’s leading edge, m: the foremost point at the full span, where the tip’s Mach cone starts.

pub fn tip_chord_m(&self) -> f64

The tip’s chord, m: the outline’s length along the flow at the full span (0 for a pointed tip).

pub fn area_m2(&self) -> f64

The polygon’s area, m².

pub fn centroid_m(&self) -> f64

Its area centroid, m aft of the root leading edge.

pub fn from_planform(planform: &FinPlanform) -> Result<Self, AeroError>

The outline of a planform: a trapezoid’s four corners, a freeform fin’s own points, and an ellipse as a polygon of 256 sides.

Errors

The planform’s own validation errors, AeroError::Unsupported for a planform this model doesn’t know, and AeroError::Domain for an outline without area.

pub fn tip_cone(&self, beta: f64) -> (f64, f64)

The area, m², and its centroid, m aft of the root leading edge, of the part of the fin inside the Mach cone from the tip’s leading edge at β = √(M² − 1): aft of the Mach line x − x_T = β (s − y), which runs inboard from the tip at the Mach angle atan(1/β).

The root is a reflection plane, so a cone that crosses it comes back: the part of the cone over the fin’s mirror image counts too, as the mirror fin’s cone crossing onto this one.

beta must be positive and finite; FinAero::loading checks the Mach number it comes from.

pub fn supersonic(&self, beta: f64, reference_area_m2: f64) -> (f64, f64)

One fin’s supersonic normal-force slope per radian, on reference_area_m2, and its center of pressure, m aft of the root leading edge, at β = √(M² − 1).

Linear (Ackeret) theory for a flat plate: each surface carries the pressure coefficient ∓2α/β, so the loading is 4α/β over the fin, uniform along every chord. Inside the Mach cone from the tip’s leading edge it is halved, as Barrowman 1967 (appendix A, p. 84) does for each strip; for a rectangular tip that is linear theory’s exact loss, C_Lα = (4/β)(1 − 1/(2βA)). The root is a reflection plane (the body). So (C_Nα)₁ = (4/β)(A_fin − A_cone/2)/A_ref, and the CP is the loading’s centroid.

beta must be positive and finite, as for FinOutline::tip_cone.

impl FinOutline

pub fn axis_moments(&self, body_radius_m: f64) -> (f64, f64)

The first and second moments of the fin’s area about the body axis, ∫ξ dA (m³) and ∫ξ² dA (m⁴), with ξ = r_t + y the distance from the axis and r_t the body radius at the fins. For a fin on a pod, r_t is how far its root lies along its span from the rocket’s axis, which may be negative.

pub fn tip_cone_axis_moments(&self, beta: f64, body_radius_m: f64) -> (f64, f64)

FinOutline::axis_moments of the part of the fin inside the tip’s Mach cone at β = √(M² − 1), with the mirror fin’s cone crossing the root, as FinOutline::tip_cone takes it.

beta must be positive and finite, as for FinOutline::tip_cone.

Trait Implementations

impl Clone for FinOutline

fn clone(&self) -> FinOutline

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FinOutline

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for FinOutline

fn eq(&self, other: &FinOutline) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for FinOutline

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for FinOutline