ShockwaveProperties.jl

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This package provides routines for computing property changes across shock waves in perfect gases. The ultimate goal is to support a solver that can be used to analyze complex interactions of shock waves in dynamic systems.

Usage

The ConservedProps and PrimitiveProps types allow for conversion between specifying gas properties as $\rho, \vec M, T$ and $\rho, \rho \vec v,\rho E$. These types will take on the SI standard units by default.

free_stream = PrimitiveProps(1.225u"kg/m^3", [2.0, 0.0], 300u"K")
u = ConservedProps(free_stream, DRY_AIR)

Property computation and conversion can be done via a myriad of functions. Any arguments given as Float64 are assumed to be in SI base units (e.g. Pa, not atm or kPa), even if the numerical value is unfriendly!

Interrogating ConservedProps and PrimitiveProps is easily done via:

• density(u): Density of state u.
• momentum(u, gas): Momentum of state u
• velocity(u, gas): Velocity of state u
• mach_number(u, gas): Mach number of state u
• temperature(u, gas): Temperature of state u
• total_internal_energy_density(u, gas): Total (internal + kinetic) energy density of state u

Other properties can be directly computed:

• pressure(u, gas): also offers overloads for certain special cases.
• static_enthalpy_density(u, gas): Computes the static enthalpy density of u. Does NOT include kinetic energy!
• total_enthalpy_density(u, gas): Computes total enthalpy density of u. DOES include kinetic energy!

"Specific" properties are related to the mass of a state, rather than its volume.

• specific_internal_energy(u, gas)
• specific_static_enthalpy(u, gas)
• specific_total_enthalpy(u, gas)

We can compute the change in properties across a shock wave from the shock normal $\hat n$ and shock tangent $\hat t$ via

stream_R = state_behind(free_stream, n̂, t̂)
u_R = state_behind(u_L, n̂, t̂)

Tests

The test suite does some basic dimensional analysis -- the speed of sound should be a velocity, pressure should be a pressure, etc. Additionally, it tests the Rankine-Hugoniot conditions for a stable shock and verifies some algebraic properties of the Billig shockwave parametrization.

Development Goals

• Extend this module with routines to compute interactions between shock waves
• Integrate this module into a larger project that can handle time-dependent situations and simulations.

Related Packages

• Euler2D.jl
• Unitful.jl
• ChainRules.jl

Contributing

Simply fork this repository and submit a pull request, should you wish.