Revamped seat placement in cabin

example/cryo_input.toml

@@ -151,6 +151,7 @@ name = "TASOPT Model with cryo fuel and HX"
     calculate_cabin_length = true 
 
     double_decker   = false #if true, the fuselage has two passenger decks
+    floor_distance  = "0 in" #Vertical distance between floors if double decker
     seat_pitch      = "30 in"
     seat_width      = "19 in"
     aisle_halfwidth = "10 in"

src/IO/default_input.toml

@@ -158,6 +158,7 @@
     calculate_cabin_length = false 
 
     double_decker   = false #if true, the fuselage has two passenger decks
+    floor_distance  = "0 in" #Vertical distance between floors if double decker
     seat_pitch      = "30 in"
     seat_width      = "19 in"
     aisle_halfwidth = "10 in"

src/IO/outputs.jl

@@ -449,12 +449,13 @@ function stickfig(ac::aircraft; ax = nothing, label_fs = 16)
 
     pax = parg[igWpay]/parm[imWperpax]
 
-    _, xseats, seats_per_row = place_cabin_seats(pax, parg[igRfuse])
+    wcabin = find_cabin_width(parg[igRfuse], parg[igdRfuse], parg[igwfb], parg[ignfweb], parg[igfloordist]) #Find cabin width
+    _, xseats, seats_per_row = place_cabin_seats(pax, wcabin)
     xseats = xseats .+ xseats0
     rows = length(xseats)
 
     println("Seats per row = $seats_per_row, Total rows = $rows")
-    yseats, symmetric_seats = arrange_seats(seats_per_row, parg[igRfuse])
+    yseats = arrange_seats(seats_per_row, wcabin)
 
     ## Plot
     if ax === nothing
@@ -552,12 +553,9 @@ function stickfig(ac::aircraft; ax = nothing, label_fs = 16)
             ax.text(0.5*(parg[igxCGfwd ]+parg[igxCGaft ]), -1.0, "CG", fontsize=label_fs-2.0, ha="center", va="center", zorder = 21)
 
         # Show seats
-        if symmetric_seats
-            ax.scatter(ones(length(yseats),1).*xseats, ones(1,rows).* yseats, color = "gray", alpha = 0.1, marker = "s", s=15, zorder = 21)
-            ax.scatter(ones(length(yseats),1).*xseats, ones(1,rows).*-yseats, color = "gray", alpha = 0.1, marker = "s", s=15, zorder = 21)
-        else
+
             ax.scatter(ones(length(yseats),1).*xseats, ones(1,rows).* yseats, color = "gray", alpha = 0.1, marker = "s", s=15, zorder = 21)
-        end
+
      # diagnostic marks
     #  ax.scatter(parg[igxftank] - l/2, 0.0, color = "k", marker="o", zorder = 21)
     #  ax.scatter(parg[igxftank], 0.0, color = "b", marker="o", zorder = 21)
@@ -1392,12 +1390,13 @@ function high_res_airplane_plot(ac; ax = nothing, label_fs = 16, save_name = not
 
     #Seats
     pax = parg[igWpay]/parm[imWperpax]
-    _, xseats, seats_per_row = place_cabin_seats(pax, parg[igRfuse])
+    wcabin = find_cabin_width(parg[igRfuse], parg[igdRfuse], parg[igwfb], parg[ignfweb], parg[igfloordist]) #Find cabin width
+    _, xseats, seats_per_row = place_cabin_seats(pax, wcabin)
     xseats = xseats .+ xseats0
     rows = length(xseats)
 
     println("Seats per row = $seats_per_row, Total rows = $rows")
-    yseats, symmetric_seats = arrange_seats(seats_per_row, parg[igRfuse])
+    yseats = arrange_seats(seats_per_row, wcabin)
 
     ## Plot
     if ax === nothing
@@ -1504,12 +1503,8 @@ function high_res_airplane_plot(ac; ax = nothing, label_fs = 16, save_name = not
             ax.text(0.5*(parg[igxCGfwd ]+parg[igxCGaft ]), -1.0, "CG", fontsize=label_fs-2.0, ha="center", va="center", zorder = 21)
 
         # Show seats
-        if symmetric_seats
             ax.scatter(ones(length(yseats),1).*xseats, ones(1,rows).* yseats, color = "gray", alpha = 0.1, marker = "s", s=15, zorder = 21)
-            ax.scatter(ones(length(yseats),1).*xseats, ones(1,rows).*-yseats, color = "gray", alpha = 0.1, marker = "s", s=15, zorder = 21)
-        else
-            ax.scatter(ones(length(yseats),1).*xseats, ones(1,rows).* yseats, color = "gray", alpha = 0.1, marker = "s", s=15, zorder = 21)
-        end
+
      # diagnostic marks
     #  ax.scatter(parg[igxftank] - l/2, 0.0, color = "k", marker="o", zorder = 21)
     #  ax.scatter(parg[igxftank], 0.0, color = "b", marker="o", zorder = 21)

src/IO/read_input.jl

@@ -279,6 +279,10 @@ readgeom(x) = read_input(x, geom, dgeom)
     calculate_cabin = readgeom("calculate_cabin_length") 
     pari[iidoubledeck] = readgeom("double_decker") 
 
+    if pari[iidoubledeck] == 1 #If aircraft is a double decker
+        parg[igfloordist] = Distance(readgeom("floor_distance")) #read vertical distance between floors
+    end
+
     parg[igseatpitch] = Distance(readgeom("seat_pitch"))
     parg[igseatwidth] = Distance(readgeom("seat_width"))
     parg[igaislehalfwidth] = Distance(readgeom("aisle_halfwidth"))

src/IO/size_cabin.jl

@@ -1,26 +1,40 @@
 """
-    place_cabin_seats(pax, Rfuse)
+    place_cabin_seats(pax, cabin_width, seat_pitch = 30.0*in_to_m, 
+    seat_width = 19.0*in_to_m, aisle_halfwidth = 10.0*in_to_m, fuse_offset = 6.0*in_to_m)
 
 Function to calculate the seat arrangement in the cabin and, therefore, the required cabin
 length.
 
 !!! details "🔃 Inputs and Outputs"
     **Inputs:**
     - `pax::Float64`: design number of passengers
-    - `Rfuse::Float64`: fuselage radius (m).
+    - `cabin_width::Float64`: width of cabin (m).
+    - `seat_width::Float64`: width of one seat (m).
+    - `aisle_halfwidth::Float64`: half the width of an aisle (m).
+    - `fuse_offset::Float64`: distance from outside of fuselage to edge of closest window seat (m).
 
     **Outputs:**
     - `lcabin::Float64`: cabin length (m).
     - `xseats::Vector{Float64}`: longitudinal coordinate of each row of seats, measured from front of cabin (m).
     - `seats_per_row::Float64`: number of seats per row.
 """
-function place_cabin_seats(pax, Rfuse, seat_pitch = 30.0*in_to_m, 
-    seat_width = 19.0*in_to_m, aisle_halfwidth = 10.0*in_to_m)
+function place_cabin_seats(pax, cabin_width, seat_pitch = 30.0*in_to_m, 
+    seat_width = 19.0*in_to_m, aisle_halfwidth = 10.0*in_to_m, fuse_offset = 6.0*in_to_m)
 
     cabin_offset = 10 * ft_to_m #Distance to the front and back of seats
     #TODO the hardcoded 10 ft is not elegant
 
-    seats_per_row = Int(2*Rfuse÷ (seat_width + aisle_halfwidth/3))
+    #Calculate the maximum number of seats per row
+    seats_per_row = 1
+    Dmin = seats_per_row*seat_width + 2*aisle_halfwidth + 2*fuse_offset #Minimum diameter for one passenger
+    while (cabin_width > Dmin) || (cabin_width ≈ Dmin) #While the required diameter is smaller than the fuselage diameter
+        seats_per_row = seats_per_row + 1 #Add one more seat
+        layout = seat_layouts[seats_per_row] #Find corresponding seat layour from seat dict
+        Dmin = seats_per_row*seat_width + (length(layout) - 1)*2*aisle_halfwidth + 2*fuse_offset #New minimum diameter
+    end
+
+    seats_per_row = seats_per_row - 1 #Subtract 1 seat to find maximum number of seats per row such that cabin_width > Dmin
+
     rows = Int(ceil(pax / seats_per_row))
 
     if seats_per_row <= 10
@@ -44,76 +58,96 @@ function place_cabin_seats(pax, Rfuse, seat_pitch = 30.0*in_to_m,
 end # function place_cabin_seats
 
 """
-    arrange_seats(seats_per_row, Rfuse,
+    arrange_seats(seats_per_row, cabin_width,
      seat_width = 19.0 * in_to_m, 
-     aisle_halfwidth = 10.0 * in_to_m)
+     aisle_halfwidth = 10.0 * in_to_m,
+     fuse_offset = 6.0*in_to_m)
 
 Helper function to arrange seats given a number of `seats_per_row`
-and fuselage radius. Assumes default `seat_width = 19"` and `aisle_halfwidth = 10"`,
+and cabin width. Assumes default `seat_width = 19"` and `aisle_halfwidth = 10"`,
 but can be supplied by the user.
 !!! details "🔃 Inputs and Outputs"
     **Inputs:**
     - `seats_per_row::Float64`:  number of seats per row.
-    - `Rfuse::Float64`: fuselage radius (m).
+    - `cabin_width::Float64`: width of cabin (m).
     - `seat_width::Float64`: width of one seat (m).
     - `aisle_halfwidth::Float64`: half the width of an aisle (m).
+    - `fuse_offset::Float64`: distance from outside of fuselage to edge of closest window seat (m).
 
     **Outputs:**
     - `yseats::Vector{Float64}`: transverse coordinate of each column of seats, measured from centerline (m).
-    - `symmetric_seats::Boolean`: flag for symmetry of seat arrangement
 """
-function arrange_seats(seats_per_row, Rfuse,
+function arrange_seats(seats_per_row, cabin_width,
      seat_width = 19.0 * in_to_m, 
-     aisle_halfwidth = 10.0 * in_to_m)
+     aisle_halfwidth = 10.0 * in_to_m, 
+     fuse_offset = 6.0*in_to_m)
 
     #Seats
     # Conditions:
     # - No more than 2 seats between any seat and the aisle
-    seats_per_row % 2 == 0 ? symmetric_seats = true : symmetric_seats = false
-
-    if symmetric_seats # seating can be symmetric
-        half_seats_per_row = seats_per_row ÷ 2
-        yseats = zeros(half_seats_per_row)
-
-        if half_seats_per_row <= 3 #Single aisle
-            yseats[1] = aisle_halfwidth + seat_width/2 #Aisle in the center
-            for col = 2:half_seats_per_row
-                yseats[col] = yseats[col-1] + seat_width #offset every seat by width
-            end 
-        else # twin aisle 
-            #If symmetric no more than 2 seats next to each other at the 
-            # centerline (I'm not evil enough to create a x-6-x seating arrangement even if "technically" allowed)
-            yseats[1] = seat_width/2.0
-            yseats[2] = yseats[1] + seat_width
-            #Aisle
-            half_seats_remaining = half_seats_per_row - 2
-            if half_seats_remaining > 4
-                @warn "Potentially trying to design a 3 aisle aircraft?
-                Seating arrangement not (yet) automatically handled, so check carefully."
-            end
-            yseats[3] = yseats[2] + aisle_halfwidth*2 + seat_width
-            for col = 4:half_seats_per_row
-                yseats[col] = yseats[col-1] + seat_width
-            end 
-        end
 
+    layout = seat_layouts[seats_per_row] #find seat layout from dictionary
+    n_aisles = length(layout) - 1 #Number of aisles
+    Dmin = seats_per_row*seat_width + n_aisles*2*aisle_halfwidth + 2*fuse_offset #Minimum required diameter
+
+    exp_aisle_halfwidth = aisle_halfwidth + (cabin_width - Dmin)/(2*n_aisles) #Expanded aisle to take up all available space
+
+    yseats = zeros(seats_per_row)
+    yseats[1] = fuse_offset + seat_width/2 #First seat is window seat
+    for i = 2:seats_per_row
+        flag_aisle = aisle_flag(i, layout) #1 if there is an aise to the left of seat, 0 if not
+        yseats[i] = yseats[i - 1] + seat_width + flag_aisle*2*exp_aisle_halfwidth
+    end
+
+    #Shift seat coordinates to start in centerline
+    yseats = yseats .- cabin_width/2
+
+    return yseats
+end  # function arrange_seats
+
+"""
+    aisle_flag(idx, layout)
+
+Helper function to find if there is an aisle to the left of a given seat.
+!!! details "🔃 Inputs and Outputs"
+    **Inputs:**
+    - `idx::Int64`:  seat index.
+    - `layout::Vector{Int64}`: seat layout map.
+
+    **Outputs:**
+    - `flag::Float64`: 1.0 if there is an aise to the left of seat, 0.0 if not.
+"""
+function aisle_flag(idx, layout)
+    #Use cumulative sum to find total number of seats to the left of a given aisle.
+    #If the difference between the cumsum and the index is exactly 1, the seat has an aisle to the left.
+    if 1 in (idx .- cumsum(layout))
+        flag = 1.0
     else
-        @info "Asymmetric seating only deals with 3 or 5 seats at the moment"
-        seating_excess_space = 2*Rfuse - seats_per_row*seat_width - 2*aisle_halfwidth 
-        yseats = zeros(seats_per_row)
-        # Start from edge and give some space based on the excess space available.
-        ind = 1
-        yseats[ind] = -Rfuse + seating_excess_space/2 + seat_width/2 
-        ind+=1
-        if seats_per_row > 3
-            yseats[ind] = yseats[ind-1] + seat_width
-            ind+=1
-        end
-        yseats[ind] = yseats[ind-1] + aisle_halfwidth*2 + seat_width
-        ind+=1
-        for col = ind:seats_per_row
-            yseats[col] = yseats[col-1] + seat_width
-        end 
+        flag = 0.0
     end
-    return yseats, symmetric_seats
-end  # function arrange_seats
+    return flag
+end
+
+"""
+    find_cabin_width(Rfuse::Float64, dRfuse::Float64, wfb::Float64, nfweb, ΔH::Float64 = 0.0)
+
+This function can be used to calculate the width of the passenger cabin from the double-bubble parameters.
+It has an optional parameter `ΔH`, which represents the distance between two floors if the aircraft is a double decker.
+If the aircraft is a double decker, the floors are assumed to be symmetric.
+!!! details "🔃 Inputs and Outputs"
+    **Inputs:**
+    - `Rfuse::Float64`: fuselage exterior radius (m)
+    - `dRfuse::Float64`: downward shift of double bubble (m)
+    - `wfb::Float64`: lateral shift of double bubble (m)
+    - `nfweb::Float64`: number of vertical webs in fuselage
+    - `ΔH::Float64`: distance between floors (m)
+
+    **Outputs:**
+    - `w::Float64`: width of cabin (m).
+"""
+function find_cabin_width(Rfuse::Float64, dRfuse::Float64, wfb::Float64, nfweb::Float64, ΔH::Float64 = 0.0)
+    #Subtract dRfuse from ΔH when there is a lower bubble; fuselage is taller
+    θ = max(asin((ΔH - dRfuse)/(2*Rfuse)), 0.0) #This assumes that floors are symmetrically distributed in fuselage
+    w = nfweb*2*wfb + 2*Rfuse*cos(θ)
+    return w
+end

src/misc/constants.jl

@@ -16,4 +16,23 @@ const pref = 101320.0
 const Tref = 288.2
 const σ_SB = 5.670374419e-8
 const p_atm = 101325.0 #Pa in one atm
-const t_h = 3600.0 #s in one hour
+const t_h = 3600.0 #s in one hour
+
+const seat_layouts = Dict{Int64, Vector{Int64}}(
+    1 => [1, 0],
+    2 => [1, 1],
+    3 => [2, 1],
+    4 => [2, 2],
+    5 => [3, 2],
+    6 => [3, 3],
+    7 => [2, 3, 2],
+    8 => [2, 4, 2],
+    9 => [3, 3, 3],
+    10 => [3, 4, 3],
+    11 => [3, 5, 3],
+    12 => [3, 3, 3, 3],
+    13 => [3, 4, 3, 3],
+    14 => [3, 4, 4, 3],
+    15 => [3, 5, 4, 3],
+    16 => [3, 5, 5, 3]
+)

src/misc/index.inc

@@ -385,10 +385,11 @@
       const igseatpitch = 306
       const igseatwidth = 307
       const igaislehalfwidth = 308
+      const igfloordist = 309
 
-      const igWfvent = 309
+      const igWfvent = 310
 
-      const igtotal    = 309
+      const igtotal    = 310
 
 # indices for turbo-electric systems - really just the electrical machines
       const ite_ratSM   = 1

src/structures/structures.jl

@@ -5,7 +5,7 @@ required to size an aircraft
 
 module structures
 
-import ..TASOPT: __TASOPTindices__, __TASOPTroot__, place_cabin_seats
+import ..TASOPT: __TASOPTindices__, __TASOPTroot__, place_cabin_seats, find_cabin_width
 
 export surfw, surfdx, fusew, tailpo, update_fuse!, update_fuse_for_pax!
 

src/structures/update_fuse.jl

@@ -94,7 +94,8 @@ function update_fuse_for_pax!(pari, parg, parm, fuse_tank)
     wbox_cabin_frac =  (parg[igxwbox]- parg[igxblend1] )/(parg[igxblend2] - parg[igxblend1]) 
 
     #Find new cabin length
-    lcyl, _, _ = place_cabin_seats(paxsize, parg[igRfuse], seat_pitch, seat_width, aisle_halfwidth) #Size for max pax count
+    wcabin = find_cabin_width(parg[igRfuse], parg[igdRfuse], parg[igwfb], parg[ignfweb], parg[igfloordist]) #Find cabin width
+    lcyl, _, _ = place_cabin_seats(paxsize, wcabin, seat_pitch, seat_width, aisle_halfwidth) #Size for max pax count
 
     #When there is a fuel tank at the back of the fuselage, there is no offset between the end of the seat rows
     #and the start of the tank. For this reason, leave a 5ft offset at back