WSF_TABULAR_RATE_FUEL¶
- fuel WSF_TABULAR_RATE_FUEL¶
fuel <name> WSF_TABULAR_RATE_FUEL Platform Part Commands ... fuel Commands ... fuel_table mode <mode-name> constant <mass-flow-value> speeds units <speed-units> <speed_1> ... <speed_2> end_speeds altitudes units <length-units> <altitude_1> ... <altitude_n> end_altitudes weights units <mass-units> <mass_1> ... <mass_n> end_weights masses units <mass-units> <mass_1> ... <mass_n> end_masses rates units <mass-flow-units> <mass_flow_1> ... <mass_flow_n> end_rates end_fuel_table end_fuel
Overview¶
WSF_TABULAR_RATE_FUEL specifies a fuel consumption rate model. It defines fuel consumption behavior at either constant rates (zero independent variables), or at variable rates based upon one to three independent variables (the choices are platform altitude, mass (weight), and speed). By default, fuel mode is ignored, and only one table is accepted; but multiple tables may be defined for different modes if desired. The active table is switched by setting the fuel mode, unless there is no table defined for the new mode, in which case the active table will not change.
This model differs from the similar WSF_VARIABLE_RATE_FUEL, in several ways; namely that WSF_TABULAR_RATE_FUEL tables must be rectangular (the number of dependent variables (rates) must match the product of the number of each of the independent variables (number of speeds * number of weights * number of altitudes)), and WSF_TABULAR_RATE_FUEL allows for 1-D, 2-D, or 3-D tables. (WSF_VARIABLE_RATE_FUEL input format is more flexible for the user, but it does not allow for 3-D table creation; it is maintained for backward compatibility with certain applications.)
Inside the fuel_table block for multi-dimensional tables, the user may list the speeds, altitudes, or weights blocks in any order. The IV listed first will be considered the “outer” slowest changing index in the table, while the last IV listed will be considered the “inner” fastest changing index. The corresponding rates block must them have the outer, middle, and inner indices changing likewise. (Internally, the table lookup routines are more computationally efficient if the IV which varies the most is selected as the inner index, which is preferred.) See Example3D at bottom of page.
Note
All independent variable arrays may be unevenly spaced, but there must be at least two values and the values must be in ascending order.
Note
In this parlance, a fuel_table is being defined, even if it is a single constant fuel flow rate value.
Commands¶
- fuel_table … end_fuel_table¶
One or more fuel_table blocks may be provided.
- mode <mode-name>¶
This specifies the fuel mode that a table is valid for. If only one fuel flow table is supplied, and is to be used regardless of the fuel mode, then do not supply this value. If multiple fuel rate tables are provided, then each table must be supplied this discriminator, to allow switching between tables. Fuel mode is accessible for change via script interface.
- constant <mass-flow-value>¶
This specifies a constant fuel consumption rate.
- speeds units <speed-units> <speed_1> … <speed_2> end_speeds¶
This specifies an independent variable arbitrary-sized array of speed values (must be in increasing order) that will apply to the independent fuel flow rate values that follow. This command is mutually exclusive with the mach command.
- mach <mach_1> … <mach_2> end_mach¶
This specifies an independent variable arbitrary-sized array of mach values (must be in increasing order) that will apply to the independent fuel flow rate values that follow. This command is mutually exclusive with the speeds command.
- altitudes units <length-units> <altitude_1> … <altitude_n> end_altitudes¶
This specifies an independent variable arbitrary-sized array of altitude values (must be in increasing order) that will apply to the independent fuel flow rate values that follow.
- weights units <mass-units> <mass_1> … <mass_n> end_weights¶
This specifies an independent variable arbitrary-sized array of weight values (must be in increasing order) that will apply to the independent fuel flow rate values that follow. (The keyword “masses” is equivalent.)
- masses units <mass-units> <mass_1> … <mass_n> end_masses¶
This specifies an independent variable arbitrary-sized array of mass values (must be in increasing order) that will apply to the independent fuel flow rate values that follow. (The keyword “weights” is equivalent.)
- rates units <mass-flow-units> <mass_flow_1> … <mass_flow_n> end_rates¶
This specifies the dependent variable values corresponding to the 1-D, 2-D, or 3-D independent variables that precede this keyword. The number of values supplied must match the product of the number of independent values in each supplied dimension (i.e. a table of 6 speeds and 4 altitudes must contain 24 fuel flow values).
Tabular Rate Fuel Example¶
fuel FuelExample WSF_TABULAR_RATE_FUEL
maximum_quantity 7000 lb
initial_quantity 6750 lb
reserve_quantity 1500 lb
mode GROUND_IDLE # Sets the mode in the Fuel Object
fuel_table
mode FLIGHT_IDLE # Sets the mode ONLY for this table (optional)
constant 800 lb/hr
end_fuel_table
fuel_table
mode CLIMB # Sets the mode ONLY for this table (optional)
altitudes
units ft
0 20000 40000
end_altitudes
mach # mutually exclusive with speeds
.25 .5 .75 1.0
end_mach
speeds
units fps
200 400 600 800
end_speeds
rates
units lb/hr
# .25 .5 .75 1.0 mach
3000 4500 5500 7000 # Sea Level
2000 3500 4500 6000 # 20 kft
1000 2500 3500 5000 # 40 kft
end_rates
end_fuel_table
fuel_table
mode CRUISE # Sets the mode ONLY for this table (optional)
weights
units lb
5000 50000
end_weights
altitudes
units ft
0 20000 40000
end_altitudes
speeds # mutually exclusive with mach
units fps
200 400 600 800
end_speeds
rates
units lb/hr
# s1, s2, s3, s4
1 2 3 4 # w1 and a1
5 6 7 8 # w1 and a2
9 10 11 12 # w1 and a3
#
13 14 15 16 # w2 and a1
17 18 19 20 # w2 and a2
21 22 23 24 # w2 and a3
end_rates
end_fuel_table
end_fuel
