domain_connectors tests

Author: Brad Carman

test/domain_connectors.jl

@@ -0,0 +1,152 @@
+using ModelingToolkit
+using Test
+using IfElse: ifelse
+
+@parameters t
+D = Differential(t)
+
+@connector function HydraulicPort(; p_int, name)
+    pars = @parameters begin
+        ρ
+        β
+        μ
+        n
+        let_gas
+        ρ_gas
+        p_gas
+    end
+
+    vars = @variables begin
+        p(t) = p_int
+        dm(t), [connect = Flow]
+    end
+
+    ODESystem(Equation[], t, vars, pars; name, defaults = [dm => 0])
+end
+
+@connector function HydraulicFluid(;
+    density = 997,
+    bulk_modulus = 2.09e9,
+    viscosity = 0.0010016,
+    name)
+    pars = @parameters begin
+        ρ = density
+        β = bulk_modulus
+        μ = viscosity
+    end
+
+    vars = @variables begin
+        dm(t), [connect = Flow]
+    end
+
+    eqs = [
+        dm ~ 0,
+    ]
+
+    ODESystem(eqs, t, vars, pars; name, defaults = [dm => 0])
+end
+
+function FixedPressure(; p, name)
+    pars = @parameters begin
+        p = p
+    end
+
+    vars = []
+
+    systems = @named begin
+        port = HydraulicPort(; p_int = p)
+    end
+
+    eqs = [
+        port.p ~ p,
+    ]
+
+    ODESystem(eqs, t, vars, pars; name, systems)
+end
+
+function FixedVolume(; vol, p_int, name)
+    pars = @parameters begin
+        p_int = p_int
+        vol = vol
+    end
+
+    systems = @named begin
+        port = HydraulicPort(; p_int)
+    end
+
+    vars = @variables begin
+        rho(t) = port.ρ
+        drho(t) = 0
+    end
+
+    # let
+    dm = port.dm
+    p = port.p
+
+    eqs = [D(rho) ~ drho
+        rho ~ port.ρ * (1 + p / port.β)
+        dm ~ drho * vol]
+
+    ODESystem(eqs, t, vars, pars; name, systems)
+end
+
+function Valve2Port(; p_s_int, p_r_int, p_int, name)
+    pars = @parameters begin
+        p_s_int = p_s_int
+        p_r_int = p_r_int
+        p_int = p_int
+        x_int = 0
+        scale = 1.0
+
+        k = 0.1
+    end
+
+    systems = @named begin
+        HS = HydraulicPort(; p_int = p_s_int)
+        HR = HydraulicPort(; p_int = p_r_int)
+        port = HydraulicPort(; p_int)
+    end
+
+    vars = @variables begin
+        x(t) = x_int
+    end
+
+    # let (flow) ---------
+    Δp_s = HS.p - port.p
+    Δp_r = port.p - HR.p
+
+    x̃ = abs(x / scale)
+    Δp̃_s = abs(Δp_s)
+    Δp̃_r = abs(Δp_r)
+
+    flow(Δp̃) = (k) * (Δp̃) * (x̃)
+
+    # 
+    eqs = [domain_connect(port, HS, HR)
+        port.dm ~ -ifelse(x >= 0, +flow(Δp̃_s), -flow(Δp̃_r))
+        HS.dm ~ ifelse(x >= 0, port.dm, 0)
+        HR.dm ~ ifelse(x < 0, port.dm, 0)]
+
+    ODESystem(eqs, t, vars, pars; name, systems)
+end
+
+function System(; name)
+    vars = []
+    pars = []
+    systems = @named begin
+        fluid = HydraulicFluid(; density = 500, bulk_modulus = 1e9, viscosity = 0.01)
+        src = FixedPressure(; p = 200)
+        rtn = FixedPressure(; p = 0)
+        valve = Valve2Port(; p_s_int = 200, p_r_int = 0, p_int = 100)
+        vol = FixedVolume(; vol = 0.1, p_int = 100)
+    end
+    eqs = [domain_connect(fluid, src.port)
+        connect(src.port, valve.HS)
+        connect(rtn.port, valve.HR)
+        connect(vol.port, valve.port)
+        valve.x ~ sin(2π * t * 10)]
+
+    return ODESystem(eqs, t, vars, pars; systems, name)
+end
+
+@named odesys = System()

test/runtests.jl

@@ -32,6 +32,7 @@ using SafeTestsets, Test
 @safetestset "State Selection Test" include("state_selection.jl")
 @safetestset "Symbolic Event Test" include("symbolic_events.jl")
 @safetestset "Stream Connnect Test" include("stream_connectors.jl")
+@safetestset "Domain Connnect Test" include("domain_connectors.jl")
 @safetestset "Lowering Integration Test" include("lowering_solving.jl")
 @safetestset "Test Big System Usage" include("bigsystem.jl")
 @safetestset "Depdendency Graph Test" include("dep_graphs.jl")

test/stream_connectors.jl

@@ -128,7 +128,7 @@ eqns = [connect(n1m1.port_a, pipe.port_a)
 
 @named sys = ODESystem(eqns, t)
 
-eqns = [connect(fluid, n1m1.port_a)
+eqns = [domain_connect(fluid, n1m1.port_a)
     connect(n1m1.port_a, pipe.port_a)
     connect(pipe.port_b, sink.port)]