Conserved fluxes across a normal gas shock
A steady planar normal shock conserves mass, momentum and total-enthalpy flux across its thin transition: [ρu]=[ρu²+P]=[ρu(h+u²/2)]=0.
Key knowledge
A steady planar normal shock conserves mass, momentum and total-enthalpy flux across its thin transition: [ρu]=[ρu²+P]=[ρu(h+u²/2)]=0. For a calorically perfect gas with γ>1 and upstream Mach number M₁>1, ρ₂/ρ₁=(γ+1)M₁²/[(γ−1)M₁²+2] and P₂/P₁=[2γM₁²−(γ−1)]/(γ+1). The physical compression branch increases specific entropy.
Values and equations
[ρu]=0; [ρu²+P]=0; [ρu(h+u²/2)]=0; ρ₂/ρ₁=(γ+1)M₁²/[(γ−1)M₁²+2]; P₂/P₁=[2γM₁²−(γ−1)]/(γ+1)
- ρ₁,ρ₂,ρ
- upstream, downstream and local mass density kg m⁻³
- u
- normal bulk speed in shock-rest frame m s⁻¹
- P₁,P₂,P
- upstream, downstream and local pressure Pa
- h,e
- specific enthalpy and internal energy J kg⁻¹
- γ,M₁
- heat-capacity ratio and upstream Mach number 1
Conditions and scope
- Shock-rest frame, one-dimensional flow, no net heat/work addition, negligible gravity change across the thin transition; h=e+P/ρ. Brackets denote downstream minus upstream; upstream/downstream bulk states have negligible viscous stress and conduction flux.
- The dissipative transition is not isentropic. Radiation losses, chemical change, magnetic stresses and collisionless plasma kinetics require adapted shock models.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read the actual conservation and gas-jump body. Flux forms are disclosed steady control-volume balances; constant ideal-gas heat capacities restrict the ratios, not arbitrary astrophysical shocks.
2026-10-10 · Independent AI editorial review: All44 exact root-authored compact records, equations/variable units/conditions and140 origin edges accepted after independently reading final6/18 with bounded primary bodies and matching prior38/122 scientific fingerprints unchanged. Exact claim/edge review is distinct from combined inventory scope and separate CLE26 approval; no entire cited books or old-corpus experimental revalidation is asserted. Receipt: cosmos-completion-independent-content-and-inventory-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- uni-cosmos-normal-shock-jump
- Revision
- core.1
- Structured reference record
- University core expansion